ment noticed as so strongly resembling the colostrum, was in no case present. Amorphous darkish masses, accompanied by various crystalline forms, were seen only. Where much discoloration existed from sanguineous or local intermixture, a strong resemblance was observed to the globule of the blood." "I cannot regard the kiestine as an unerring test of preg nancy. I have already shown that it is present under other conditions of the system; and even where pregnancy exists, I am not satisfied that this indication is not always observable. I am convinced too, that the kiesteine is not always distinguishable from other pellicles which appear on the surface of the urine. At least, I am bound to say, that, in the absence of other indications, I should sometimes have found myself unable to distinguish between them. Not that they are gener ally liable to be confounded; but between the imperfectly developed pellicle of the one character, and the best simulation of it which is sometimes presented by others, the distinction is too slight to be satisfactory or unfailing. But with the qualifications which these remarks imply, I have no doubt that the pellicle which has been denominated kiesteine is among the best, if indeed it be not the most certain, of the earlier indications of pregnancy. I resorted to it habitually in my diagnosis in the obstetric wards of our hospital, and with constantly increasing confidence." "The result of my observations may be summed up in the following general conclusions: 1. That the kiesteine is not peculiar to pregnancy, but may occur whenever the lacteal elements are secreted without a free discharge at the mammæ. 2. That though sometimes obscurely developed and occasionally simulated by other pellicles, it is generally distinguishable from all others. 3. That where pregnancy is possible, the exhibition of a clearly defined kiesteinic pellicle, is one of the least equivocal proofs of that condition; and 4. That when this pellicle is not found in the more advanced stages of supposed pregnancy, the probabilities, if the female be otherwise healthy, are as 20 to 1 (81 to 4) that the prog nosis is incorrect." "Since this dissertation was submitted to the Medical Faculy of the University of Pennsylvania, two papers on this subject have appeared; one by Mr. Letheby, in the London Medical Gazette of Dec. 24, 1841, and an elaborate paper by Dr. Stark, in the Edinburgh Medical and Surgical Journal, for January of the present year. The facts observed by Mr. Letheby accord generally with my own. He found 'unquestionable evidence of kiesteine in forty-eight out of fifty cases between the second and ninth month of utero-gestation,' and was unable, like myself, to 'account for its absence in the two exceptions.' In seventeen non-pregnant women he found no indication of its presence; but detected it in the urine of ten suckling women, immediately after delivery, and onwards to periods between the second and sixth months, when it disappeared. The few microscopic results which he gives coincide also with my own.", Dr. Stark's paper is devoted to the signs of pregnancy, and among the rest to the state of the urine. He refers succinctly to his own observations relative to the kiesteinic pellicle, which he supposes to be derived from the suspended sediment; and he asserts that there exists a relative proportion between these and the earthy salts which enter into the composition of the urine. His paper derives its principal interest from his researches into the character of the sediment. In the natural sediment of the urine of pregnancy, he was unable to detect the presence either of albumen or caseum by acids, alkalis, or alcohol, with the aid of heat; but when he added a certain quantity of milk to the urine, both these principles were discovered readily by the aid of acids, the other tests producing no effect: when milk was added in smaller quantities, however, it was undiscoverable by any reagent. Being unable to refer the sediment to any of the known deposites of the urine, though his investigations had immediate reference to its distinctive characters, he employed ether to effect a separation of the animalized matter which he thought it might contain, and he supposes that he succeeded by this means in detecting a substance entirely different from any heretofore known. Failing to determine its constitution by chemical agents, he resorted to the microscope. He here found that this sedimentitious matter, whether examined while yet held in solution by the recent urine, or when it had assumed the form of a deposit, or when it had been disengaged by ether, was composed of distinct transparent or pellucid' globules, which when in their sedimentary condition bore a striking resemblance to the caseum globule of recent milk, but which when pellucid bore an equally strong resemblance to the serous or albuminous globule, Dr. Stark now reduced the question to very narrow bounds, by inquiring as to the identity of this sedimentary matter with albumen, caseum, fibrine, and gelatine. He thinks that its. minute structure and chemical properties sufficiently distin guish it from the two first;-from albumen, because it dissolves, instead of coagulating, upon the application of heat; from caseum, because it is soluble in nitric and sulphuric acids, which exert on this principle a very contrary action. From fibrine, it has necessarily a still greater difference. There remains gelatine; and compared with this, the distinction was less striking. The globules of both under the microscope, were similarly formed, both were soluble in the acids and alkalies, and by the aid of heat. The only distinctive particular seems to have been the action of tannin, which, as is well known, precipitates gelatine from its solution in water. Some of the natural sediments, dissolved in boiling water, and cooled to a blood heat, were treated with a decoction of galls: a flocculent precipitate was at once produced; but instead of gelatinizing upon cooling-it was deposited; and instead of becoming more solid and more easily separable, upon reboiling, it again underwent solution. Upon these grounds he attains the conclusion, which I give without comment, "that this substance is a matter sui generis, an elementary substance or principle, forming in some measure a connecting link between the albuminous and gelatinous elementary principles. This substance he proposes to designate by the name of 'Gravidine.' It is unnecessary to say, that this discovery of a new or ganic principle, if confirmed by future investigation, will be a matter of great interest. I must confess, however, that the distinctive characteristics of the new substance do not seem to me very decidedly marked in the results announced by Dr. Stark; and such is the complex, and often deceptive nature of the investigations of physiological chemistry, that we have a right to wait for renewed experiments before admitting too implicitly the certainty of those he has described. Dr. Stark considers that his experiments entirely subvert an opinion which has met with some favor regarding the theory of these appearances. Ever since the publication of Nauche's paper, the supposed presence of caseum in the urineof pregnancy has countenanced the idea entertained by Bird and others, already referred to, that the elements of the milk (not, as Dr. Stark infers, the milk itself,) might probably exist in the urine:—as, however, the matter is neither milk nor caseum, a theory based upon their presence must necessarily fall. The conclusion may be a correct one so far as the chemical analysis is concerned; and yet the connection between the ki estine pellicle and the mammary secretion may be adequately proved by other evidence. If even the Gravidine be regarded as a new organic principle, its properties are not so peculiar, nor its analogies with caseum so remote, as necessarily to imply the operation of different causes in the formation of the two. I have already mentioned my conviction, founded on per sonal observations, that the unmodified caseum is not found in the urine; but the presence of the colostral appearances under the microscope, and the numerous phenomena which I have described as attending the presence of the Kiesteine leave me no room to doubt its intimate connection with the condition of lactation." Dentition of Children at the Breast. By Professor TROUSSEAU-Suspecting that the generally received ideas on the dentition of children were not correct, M. Trousseau, from statistical observations not very numerous, has come to conclusions slightly different from the opinions generally believed. Period at which the first tooth appears. This has been determined in 25 children; 13 boys, and 12 girls. It appeared as follows: In 2 boys at 3 months. 2 In I girl at 3 months, why. Extremes, 3 months, 14 months. 2 months, 14 months. 6 months. The average time, then, at which the first tooth appears is, from these results, six months and a half; while the general belief at present is, that at eight months it makes its appearance. The common opinion that little girls are more precocious than boys, is also corroborated, as we find a difference. of a month between the appearance of the first tooth in boys and in girls. The first tooth is in general one of the middle inferior incisors. Of twenty-eight children this was the case in twentyfive. In two, a middle superior incisor appeared first; and in a little girl, the first molars preceded all the others. 2 Period at which the second tooth appears. The twenty-five children in whom a middle inferior incisor first showed, had for their second tooth, the other middle inferior incisor. The common opinion is, that this second tooth appears almost at the same time as the first; and it is quite correct. In twentyfive children, the time that elapsed between the first and se'cond tooth, was, 1 day in 4 children; 2 days in 2 children; 3 days in 1 child; 8 days in 3 children; 15 days in 7 children; 30 days in one child; 90 days in 1 child. In six the time could not be determined by the mother. The middle superior incisors appear next after the two middle inferior. In eighteen children, fifteen had these teeth after the middle inferior incisors. The time that elapses generally between the cutting of the inferior and superior incisors, is more variable than is generally supposed. In thirteen chil dren in whom M. Trousseau was able to verify this; there was a lapse of 8 days in 2 children: 1 month in 3 children; 2 months in 3 children; 3 months in I child; 4 months in 1 child; 5 months in 2 children; 10 months in 1 child. In general, then, there is a considerable interval between the appearance of the second first and the second second teeth. It may be established as a general rule, almost without any exception, that after the appearance of these four teeth, the two lateral superior incisors next cut the gum, and then the two inferior ones, so that the child has only two teeth in the lower jaw, while it has four in the upper. It is curious, M. Trousseau says, that this fact, so well known to mothers who have brought up several children, should be unknown to those who have written specially on the subject. Whilst a considerable period takes place between the first appearance of the inferior and superior incisors, the four superior incisors follow each other at a short interval. After these six teeth have come through, some time elapses before the next, which are generally believed to be the two lateral inferior incisors, appear. M. Trousseau, however, says, that as a general rule, one or several molars, and sometimes even the canine, are protruded before them. After the cutting of the four molars, and the two inferior lateral incisors, another considerable interval of time elapses, when the four canine successively appear; and then after another period, at the age of from twenty-four to thirty months, rarely sooner, the second set of molars come out. In the second part of his work, M. Trousseau treats of the diseases incidental to teething, and especially of the diarrhoea accompanying it, and he combats the opinion so prevalent, |