cally or pathologically, are correct upon the those in relation with critical days, the catawhole. menial period, &c. These phases of develThe preceding remarks must serve as an opment, in birds, are indicated in most inexposition of the doctrine of the ancients re-stances by moulting, a process in which the garding septenaries. It now remains to in-mucous membrane of the whole system is quire how far these doctrines are true, and implicated, as well as the skin and its appenwhat practical benefits can be derived from dages. In all birds a moult takes place sooner them. or later after being hatched, but it does not

In man, life may be divided into three great clearly appear what dentition (for this is periods. The first may be defined as extend-analogous to moulting) corresponds to this ing from the commencement of intra-uterine moult. I am inclined to think, however, existence to the complete evolution of the sex- that its analogue is neither the first nor the ual organs; the second comprises the period second dentition, but both. The plumage in which those organs are active; and the characteristic of the sexes begins to appear at third extends from the period when they cease this moult, and it is always a period of danto act to the termination of life. These are ger to domesticated birds, as peacocks, turclear and well-defined epochs, but it is diffi-keys, pheasants, canaries, &c. As iron is cult to fix their precise dates, for all vital recommended for their cure, the state of changes are gradual, and do not admit of ex- health seems analogous to the chlorotic conact limitation. Similar difficulty is experi-dition of young people. Buffon remarks that enced in the attempt at a natural classification the period is analogous to dentition in chilof animals, and is only overcome by having dren, meaning, I suppose, the first. In turtransition or inosculent groups. We may keys it occurs in six or eight weeks after the adopt a like expedient here. The first period hatch; in peacocks, four weeks; in partridges may be stated as comprising 21 years, the twelve weeks; in canaries, five or six weeks. second 28 years, and the third 21 years. The The period during which the eyes of some secondary periods of the first great period will mammals are closed after birth is worthy be seven, namely,-1, intra-uterine life; 2, notice, this being evidently heptal. In whelps the period between birth and the first denti- it is fourteen days; in bear-cubs, twentytion; 3, the time occupied by the first denti-eight days. It may be possible that the idea tion; 4, the period between the first and of Diocles, respecting the first use of the eyes second dentitions; 5, the time of the second after birth, may have some foundation in dentition; 6, the period between the latter truth. That some change takes place in the and commencing puberty; 7, the time occu-infant in the eighth week may be fairly inpied in the evolution of the reproductive or- ferred from the fact that the man with ichgans. The second great period will comprise thyosis, (the porcupine man) whose history three minor periods. First, the perfecting of is detailed in an early volume of the "Philoadolescence from 21 to 28; secondly, the cli-sophical Transactions," (1731), and who max of development, or status of life, from transmitted his disease to his progeny, stated 21 to 42; and thirdly, the septenary of de- that the cutaneous affection appeared in himcline in the reproductive powers, extending self when about seven or eight weeks old; from 42 to 49, after which latter age concep- and we find, subsequently, that his six chiltion rarely takes place. The third comprises dren had the disease first at the same age. also three periods, the first from 19 to 63, the The tusks of young elephants are shed in the grand climacteric; the second from 63 to 70, twelfth or thirteenth year, but the cheek-teeth or old age; and the third from 70 to death, appear six or seven weeks after birth. But the years of atas ingravescens, or decrepitude. the seventh and fourteenth days of infants In fixing these epochs I have followed the seem to constitute periods. M. Quetelet finds generally received septennial division, being that the weight of an infant diminishes sensireluctant to make any innovation thereon. It bly immediately after birth, and does not bewould, I think, however, be more in accord-gin to increase until after the seventh day. ance with modern science to date, not from In 1810, Dr. Holland published a table of the birth, but the conception of the individual. If this be done, each great period should be calculated as commencing nine solar months earlier.

deaths in newly-born infants from tetanus in the Westmann islands, Iceland, and denoted the days most fatal: in 185 deaths, 75 took place on the seventh day. A few hours must Those of the readers of THE LANCET Who be allowed for retarded labor and errors in may have perused the first paper in my series computation, but if we take the sixth, sevwould observe that the periods of development enth, and eighth days, the average of deaths in insects were more particularly alluded to is 37 2-3 daily, while the average of the reas establishing the minor periods, namely, maining 18 days is only 4. An increased

mortality took place on the fourteenth day curred concurrently with a period of about

after birth. (Edin. Med. and Surg. Jour. vol. viii., p. 207.) The fourteenth day after birth is marked also by changes in the lower animals.

forty weeks after birth, or with the first or second dentition. I have collected 17 instances of this kind, with the following results: -5 were males and 12 females; of these, 3 The order of development of the teeth in males and 1 female were more fully develman is an interesting subject, as upon it we oped than usual at birth; of the remaining, 1 must principally rely for determining the pe-male and 3 females exhibited the phenomena riods of development in the system generally. of incipient puberty at the age of eight or Mr. Goodsir's researches are exceedingly in-nine months, 1 at two years, 1 at two years teresting, as marking their gradual hebdoma- and a half; 6 had the catamenia or were dal evolution in the embryo and fœtus, but fully developed at three or four years, and 3 are not sufficiently accurate for our purpose were perfect women at 8 years. Two of the as to the time when the changes occur. Pre- latter were pregnant at that age, and the reviously to the eruptive stage, or common den-maining one lived to have a numerous family. tition, there are three phases of development: In all these instances in which the growth of the papillary, commencing about the seventh the teeth is alluded to, it is sufficient to state week of fatal life, the follicular in the tenth, that it was irregular. (Vide Lond. Med. and and the saccular in the fourteenth week, Phys. Jour., vols. vii., xxiv., xxv., lxv.; New which continue until the eruptive stage, about Lond. Med. and Phys. Jour., vol. ii.: Med. the seventh month after birth, when the four Chir. Transactions, vol. i., ii., xii., &c.) central incisors present themselves. After It is probable, indeed, that sexual developthis period the other teeth appear at intervals ment takes place in these cases, as well as not yet precisely fixed, the first dentition be-normally, per saltum, an effort being made ing terminated, however, by the end of the just at the time when certain teeth are apthirty-sixth month. All is then quiescent for pearing; after the tooth is perfected, and the three or four years, or until about the middle constitutional effort has ceased, so also will or end of the seventh year, when the first true molar makes its appearance, and which, according to Mr. Goodsir, is analogous to the milk-teeth in its mode of formation, the permanent central incisors appearing about the same time. Mr. Saunders has proposed to make use of the development of the permanent teeth to ascertain the ages of factory children, and his table, deduced from several hundreds of observations, is as follows:The first true molars appear at the age of

The central incisors

7 years.

8

9

10

11

12 to 121
12 to 14

The third pair of molars, the dentes sapiente, appear later; according to Meckel and Goodsir, at from 16 to 20 years.

the nisus in the ovaria or testes. Occasionally the catamenia appear in young females about the age of twelve or thirteen, for once or twice, when the canine teeth are protruding; and then cease, to re-appear only when puberty fairly commences, about the age of fourteen, the period at which the second molars burst forth. Taking the appearance of the teeth as indicating the periods of a constitutional nisus, we must look upon the third molar teeth as marking the commencement of that last stage of development in which the individual is perfected.

Upon a review of dental development it will be observed that the periods lengthen as age advances First, the primary papillæ appear hebdomadally in the fatal state; then, during the eruptive stage, the teeth succeed each other at intervals of six or eight weeks, but afterwards of three or four months. During the second dentition the interval is at first a year, then a year and a half, or two years, then four or five years. The dentition observed at an advanced age I shall notice subsequently.

In animals generally the development of the teeth is closely connected with the evolution of the reproductive organs. The tusks of the stallion, wild boar, and walrus, are sexual, and are simply canine teeth of an unWhat relations have these dental periods usual size Upon inquiring how far the teeth to functions, disease, and death? First, as are related to the reproductive organs in man, regards function. The development of the it is interesting to observe that there is occa-thorax in males, concurrently with the testes, sionally a coincidence of development be-alters the functions of the lungs; besides, as tween the two, which, a priori, would seem plants consume a larger quantity of oxygen improbable. From time to time instances of precocious puberty have been recorded, and it would appear that the change in the ovaria or testes, and in the system generally, has oc

while flowering, or, in other words, when at puberty, we may look for an increased consumption in animals and man at puberty. Now, M. Andral has found that the excretion

of carbonic acid from the lungs is greater in maximum, or in other words, it is the period males than in females after eight years of age; when man can most depend upon his actual in the former, at puberty, the quantity sud-existence. The periods of dentition (and denly increases, while in the latter, when the also the analogous periods of moult in anicatamenia commence, the excretion is as mals) are the times when the individual is suddenly arrested, and remains stationary in most liable to disease, and, during the first quantity, and almost as small as in child- dentition at least, to death. Mr. Farr's tables hood, so long as the monthly uisus continues: show this very strikingly. The eruption of when this ceases, or when pregnancy takes each individual tooth, both in the first and place, the quantity immediately increases. In second dentition, is invariably attended with males the excretion begins to diminish in considerable constitutional disturbance in deliquantity at the age of 30; between 16 and cate persons, so considerable, indeed, during that age it is double that excreted by the fe- even the eruption of the third molars, or male. M. Bourgery made experiments on the dentes sapientia, as sometimes to create alarm. capacity of the lungs in the two sexes at dif- The great mortality in the first four months ferent ages. He found that the volume of the of infantile existence seems to be connected respiration of the male doubles that of the fe- rather with congenital debility, many only male, and that the plenitude in both sexes breathing once or twice; or with extraneous occurs at the age of 30. The volume of air circumstances, as early exposure to cold, &c. required by an individual in an ordinary res-Antecedently to the first dentition infants are piration augments gradually with the age. remarkably free from the attacks of prevalent The relations between the ages of 7, 15, 20, and fatal epidemics. and 80, are geometrical, and represented by the numbers 1, 2, 4, 8. (Dublin Medical Press, March 15, 1843.)

The development of the reproductive organs has a secondary influence on the system at large, and modifies its diseases. In males The muscular system acquires additional (as just stated) the thoracic region is more development during the second dentition, and fully developed, the respiration and circulain boys the respiratory movements are pro- tion becoming more active. We can thus portionally active; but it appears that they explain the liability of youths to diseases of are not so in girls, and we can thus explain the heart, and to hæmoptysis and other pulthe greater prevalence of chorea in the latter monary affections. In both sexes the kidneys sex at the second dentition. The less liability are acted upon by the ovaria and testes, and to convulsions, on the access of febrile affec- their functional activity is exalted or dimintions, may be connected with this increased shed. Hence a class of diseases is observed muscularity. According to Quetelet, during childhood the lumbar power of boys is about one-third more than that of girls; towards the age of puberty one-half; and the strength of a developed man is double that of a woman. These data correspond so closely with those of Bourgery and Andral, on the respiratory functions, that the coincidence cannot be casual.

in youth analogous to those observed in spring and autumn. In females with the gouty diathesis this ovarian action upon the kidneys develops those irregular forms of hysteria which so often baffle the skill of the routinist. The irritation set up in various organs connected anatomically or physiologically with the ovaria, as, for example, the organs of voice, the mammæ, the pelvic visM. Quetelet also shows that the ratio of cera, the dorso-lumbar cord, and those parts growth of a child in height diminishes as its of the encephalon associated with the sexual age increases, until the end of the first denti-instinct, is so great as to stimulate inflammation. From the fourth or fifth year the increase of stature is almost the same in each year up to the sixteenth, when it diminishes gradually until the attainment of the 25th year, if a male, but earlier if a female. The weight follows the same rate of increase as the height.

According to Quetelet the viability between birth and complete puberty varies considerably at different ages. From birth to the completion of the first dentition the mortality is great; it then diminishes, and at the age of five years the probability of life attains its maximum. At 13 or 14 a favorable change is agam voserved; viability is then at its

tion, and being founded on an arthritic diathesis it assumes the migratory character of arthritic disease. Thus the diagnosis and the treatment are rendered hopelessly difficult to the practitioner whose " practical" knowledge is not derived from the true source of practical skill, namely, a knowledge and just appreciation of physiological laws.

These views respecting the ovarian and renal origin of the anomalous forms of hysteria are developed at length in my published work; as they are based on the solid foundation of physiology applied to pathology, I venture to hope that in proportion as the solido humoral pathology of the day is per

72

fected, their correctness will be admitted. It coincident. I gave, also, an illustration of
is manifest that as the due evolution of the this inference, in which twins (two boys)
system in youth is necessary to healthy and went through dentition, and were attacked by
useful manhood, and to a comfortable old indisposition and infantile disease always at
age, the laws of development and their bear- the same time. Stoll seems to have suspect-
ing on pathology are of the first importance. ed some coincidences of this kind when he
To consider the remaining periods of life, remarked-"Utile est observare necne sem-
(Ratio Meden-
namely, the status and decline, would be to per eo tempore quo infans corripitur epilepsia
review the whole domain of pathology. After matri fluant menses, necne."
the age of 30 or 35 the abdominal viscera playdi, Aphor. 209.) What is true of the minor
Phthisis carries off the
a more important part in health and disease, periods is true of the major, and examples in
and often give the latter its distinguishing proof are numerous.
characteristics. It is worthy of remark, that members of a family as they successively ar-
rive at a certain stage of development; in-
just as precocious puberty is occasionally seen
sanity appears at a known age in all the
in infancy, so an attempt at rejuvenescence is
sometimes male in old age, about the grand members of another; apoplexy and paralysis
climacteric, or later. There is a fresh eruption in those of a third, &c. Dr. Martin has re-
A person
of teeth, a complete set sometimes protruding, corded a striking example of this periodic de-
the reproductive organs reassume their acti-velopment of hereditary disease.
vity, and the catamenia again appear, as well named Moses Le Compte, who was blind,
as other phenomena, observed only during had thirty-seven children and grand-children
the evolution of the system. Stoll, Good, and that became blind like himself. The blind-
others, have recorded instances of this kind. ness is described as commencing in all about
That this is not mere chance is shown by the the age of fifteen or sixteen, and terminating
fact that a similar change is observed in the in total deprivation of sight about twenty-two.
lower animals. Gallinaceous albinos-pheas- (Quoted from the Baltimore Med. and Phys.
ants, for example, according to Temminck, Jour., vol. 1., p. 394.) But, indeed, many
will assume all their former brilliancy of similar instances might be quoted from nu-
merous writers, which, if less striking, are
plumage, proving (since the latter is strictly
sexual) that the reproductive organs are again equally instructive. Such may be found, for
active. The hen of the gallinaceous and example, in Dr. Holland's interesting essay
other birds occasionally approximates in plu- on the Hereditary Transmission of Disease.
mage to the cock, and ceases laying. It has Vide Medical Notes and Reflections, p. 27,
been shown by Yarrell that this change is 1st edition.) The assiduous cultivation of
this branch of vital proleptics promises the
connected with a shrinking of the ovaries;
but sometimes the male plumage falls off, and most valuable and practical results. Every
that of the female is redeveloped, and then family should possess its medical history,
the bird lays eggs again. Nature herself here with exact dates, just as a nation its archives,
exhibits something like perpetual youth, and and illustrated by a series of Daguerreotype
those who wish for this grand desideratum portraits. The physician could then have
would do well to inquire closely into the cir-data that might enable him to anticipate he-
reditary disease, and if not to prevent its de-
the rejuvenes-
cumstances which accompany
velopment, at least to predict its occurrence
cence described.
and modify its influence. But, indeed, if the
laws regulating the hereditary transmission
and periodic evolution of morbid states be
once clearly ascertained in all their relations,
would be obviated, and its value proportion-
much of the imperfection of medical science
ally exalted.

The periods of life have a much more im-
portant and practical bearing on the periodic
development of hereditary disease. It is as
certainly true that all the peculiarities of the
parent are transmitted to the offspring, as that
the whole is equal to the sum of all its parts.
Some or many of the peculiarities derived
With our countryman, CLIFTON WINT-
from the one parent may be negatived by pe-
culiarities derived from the other, or even by RINGHAM, the school of mathematical physi
extraneous circumstances, and not be mani-cians seemed to expire. With section A,
Mathematics and Physics," in the
fest in the offspring; but they are not the less that of
surely there, and may and do reappear in the BRITISH ASSOCIATION of Cork, the labours of
third or fourth generation. In a previous medical men have as little connection as with
paper I observed that as conception took any of the departments into which the meet-
place at a minor period (the catamenial), the ings were divided. Yet the time may come
minor periods, at least, of the offspring, when the data of physiologists will be sub-
would correspond to those of the mother, and mitted to mathematicians, and figures be al-
that if twins dated their conception from the owed to express the mysterious laws of or
same hour, the periods of their life would beganic life.-Edit. L. Lancet.

NEW ERA IN THE PRACTICE OF MEDI

CINE.

Lectures delivered at the Egyptian Hall,
Picadilly, London, 1810.

BY SAMUEL DICKSON, M. D.*

LECTURE I.

FALLACIES OF THE FACULTY.

had an opportunity of being introduced to his equally celebrated countryman and contemporary Baillie. Curious to know Gregory's opinion of the man who then swayed the medical sceptre of the metropolis, his friends asked him what he thought of Baillie. Baillie," he replied, knows nothing but Introduction Phenomena of Health and wards wittily rejoined, physic" in revenge for which, Ballie afterSleep-Disease and its Type-Causes. Gregory knows every thing but Physic." But what was Dr. Gentlemen, We daily hear of the march Baillie's own opinion of his profession after of intellect, of the progress of perfection of all? I do not now allude to his language many branches of science. Has MEDICINE during the many years he was in full practice; kept pace with the other arts of life-has it then, doubtless, with the multitude who fallen short or excelled them in the rivalry of thronged his door, he really believed he knew improvement? Satisfactorily to solve this a great deal; but what did he say when he question, we must look a little deeper than retired from practice, and settled at his counthe surface-for TRUTH, as the ancients said, try seat in Gloucestershire? Then, without lies in a WELL,—meaning thereby that few the slightest hesitation, he declared he had people are deep-sighted enough to find it out.no faith in Physic whatever! Gentlemen, In the case of Medicine, we must neither be you must not from this imagine that the formystified by the boasting assertions of disin-tunate doctor intended to say that the world genuous teachers, nor suffer ourselves to be all along had been dreaming when it bemisled by the constant misrepresentation of lieved Opium could produce sleep, Mercury the medical press-for these publications for salivate, and Rhubarb purge. No such thing the most part are nothing better than mere he only confessed that he knew nothing organs of party, and, like the newspapers of of the manner of action of these substances the day, do often little more than crush and on the body, nor the principle upon which cry down any truths that militate against the they should be used. Now, what would interest of the schools and coteries they are you think of a sailor who should express employed to serve. The late Sir William himself in the same way, in regard to the Knighton was at the head of his profession; rudder and compass, who should tell you he was, moreover, physician to George the that he had no faith in either instrument as Fourth. Joining, as he did, much worldly a guide to steer a vessel by?-why, certainly wisdom and sagacity to a competent knowl- that he knew nothing of the profession by edge of the medical science of his age, his which he gained his living. And such really opinion of the state of our art in these later was Dr. Baillie's case. The great bulk of times may be worth your knowing; more mankind measure the professional abilities especially as it was given in private, and at of individuals solely by their degree of repua period when he had ceased to be pecuni- tation-forgetting Shakspeare's remark, that arily interested in its practice. In one of his a name is very often got without merit, and private letters, published after his death, he lost without a fault. That Baillie actually thus delivers himself:-"It is somewhat attained to the eminence he did, without any strange that, though in many arts and sci- very great desert of his, what better proof ences improvement has advanced in a step of than his own declaration ?-a declaration regular progression from the first, in others, which fully bears out what Johnson tells us it has kept no pace with time; and we look in his life of Akenside: "A physician in a back to ancient excellence with wonder not great city, seems to be the mere plaything of unmixed with awe. Medicine seems to be fortune; his degree of reputation is for the one of those ill-fated arts whose improve- most part totally casual; they that employ ment bears no proportion to its antiquity. him know not his excellence-they that reThis is lamentably true, although Anatomy ject him know not his deficiency." But still, has been better illustrated, the Materia Medica some of you may very naturally ask, how enlarged, and Chemistry better understood."* could Dr. Baillie, in such a blissful state of Dr. James Gregory, a man accomplished in ignorance or uncertainty, contrive to preserve all the science and literature of his time, was for so long a period his high position with for many years the leading physician of Edinburgh; but he nevertheless held his profession in contempt. On visiting London, he

The readers of the Dissector will find these Lectures extremely rich.

10

the professional public? This I take to be the true answer: the world, like individuals, has its childhood-a period when, knowing nothing, it may fairly be excused for believing any thing. When Baillic began practice,