more injected with red-vessels, than they are previous to the setting up of that condition. 6. Menstruation gives rise to a congested state of the uterine vessels, as is manifested by the appearance. 7. The progression of the Graafian follicles, or ovisacs, towards the surface of the ovaries, their appearance under the peritoneal coat as copper-coloured macules, the absorption of that membrane, and of their own tunics, and the occurrence of a solution of their continuity at the point at which they unite, take place in the menstrual, just as in the anti-menstrual life. 8. The shape assumed by the ovisacs, depends on the part of the ovary they occupy. 9. The ovisacs of the human female do not require the presence of menstruation for their development or rupture. 10. The only circumstances essential to the discharge of ova, are the rise of the vesicles which contain them to the surface, and the gradual thinning of the ovarian peritoneum, and of the coats of the ovisacs at their point of union. 11. The appearances of the ovaries, Graafian vesicles, and of the blood contained in the latter, subsequent to their rupture, vary according to the time at which they are examined, and the absorbing power of the individual. 12. In case of the recent evacuation of an ovisac, the peritoneal coat of the Ovary is occupied by a jagged slit or opening, having a florid vascular areola; in those of longer standing the opening is covered over, with the exception of a minute circular foramen in the centre, or, where the slit has been of great length, of two such openings, with new tissue, surrounded by claret-coloured margins. 13. The blood generally contained in the ruptured vesicles, is seen at first as a florid coagulum, next having its centre only scarlet-coloured, and its periphery more or less black frequently the clot has a gamboge colour; lastly, the clot. is found in different stages of absorption; sometimes in every variety of the uterine state the ruptured follicles are found empty, or containing only an aqueous fluid. 14. The coats of the ruptured ovisacs have been found in four different general conditions, apparently dependent on the relative degree of organisation, each class presenting also modifications of their respective characteristics. 15. The first class was distinguished by the attenuated state of the coats of the ruptured ovisac, and by the total absence of any organic changes in these, different from their condition previous to their discharge; the only alterations observable being A. The mechanical dying of their coats, of an inky black colour, proceeding from their contact with their contained decomposed blood. B. The dying of their coats of a yellow tint, from their enclosed clot of blood having become converted into a rust-coloured pigment, not unlike some of the denser sputa of acute pneumonia. This first class of ruptured ovisacs was found indifferently in all ages and states subsequent to puberty. 16. The second general class of ruptured vesicles was characterised, in addition to the presence of blood within their cavities, by organic changes in their coats-it was observed, A. Under the form of soft white bodies of a yellowish, fatty aspect, having the outer coat much thickened, their inner remaining as a delicate diaphanous pellicle. B. As dense, white bodies of a whitish, shining, firm structure, their inner coat being the seat of these changes, and their outer adhering loosely as a transparent, pellicular layer. A. The discharged ovisacs which constituted the soft white bodies were seen 1st. At a very early period after their discharge, their walls distended with a coagulum, and painted with turgid vessels. 2. In a similar state, except that the inner membrane had a swollen, puffy look, and from the looseness of its adhesions might be easily gathered into folds. 3. At a period so advanced, that the clot had become uniformly black and solid, the inner layer was easily separated from the more external, which was also thickened and become yellow. 4. At a point still more advanced, the outer, thickened, yellowish coat had become corrugated into wrinkles or folds. 5. At a still more advanced period, the cysts were converted into yellowish white, and generally globular bodies. 17. These white bodies (corpora albida) were found in every variety of uterine condition subsequent to the establishment of menstruation, but never before it. 18. White bodies, as such, had no necessary connexion with the gravid condition. 19. The third general class of discharged ovisacs was distinguished by the secretion of an organized, yellow-coloured, brain-like, granular matter. 20. The fourth general state of the ruptured ovisac was peculiar to the impregnated and lactating female in the period between the eighth and thirteenth month after conception, and appeared to be a conversion of the forms already described, arising out of a higher and more perfect organization. Down to the seventh month of pregnancy the cysts contained in the ovaries did not differ in any respect from the cerebriform bodies found in the unimpregnated state, unless that they were sometimes plumper, more vascular, better developed. 21. The rose or red-coloured (corpora rubra) were not always present in the gravid or recently puerperal states. 22. The excess of corpora albida over every other physiological appearance in the impregnated ovary, seemed to result sometimes from the gradual obliteration of the vessels of the highly vascular outer coat, and cerebriform matter lining it. 23. In many puerperal women bodies of identical character, but in different stages of progression, were often found together, and it was then supposed that the best organised cysts were at once the most recent, and those which had furnished the fecundated ova. 24. In other pregnant women, in none of which had there been twins born, two bodies of a similar kind, and of equal organization, were found either in the same ovary, or in the two: and in such it was impossible to determine the productive from the non-productive vesicle, and their rupture was therefore believed to have been coetaneous, and that while the ovum of the one only had been fecundated, the coats of both, alike capable of taking on a higher organization, had been exposed equally to the increased ovarian circulation consequent on utero-gestation. 25. The simultaneous development in the ovaries of two corpora rubra was not met with in the present series of observations--a circumstance, which may be attributed, however, to the comparatively limited nature of the latter. 26. There was no evidence that granular matter was ever secreted around an unruptured Graafian follicle. 27. A nippled or cumulated protuberance of the surface of the ovaries over a granular cyst; crateriform openings on the apices of the latter, with vascular edges; and serrated "internal cicatrices," traversing the interior of the cephaloid bodies; and blood-vessels ramifying on their granular matter, were not peculiar to the gravid female. 28. Immediately on the arrest, and during the suspension, of menstruation, by any cause, the Graafian vesicles were found less vascular, thinner, and smaller, than their normal structure in menstrual life. 29. The co-existence of this modification of the ovisacs with the presence of white bodies in the ovaries, was not peculiar to the gravid state. 30. The obliteration of the cicatrices peculiar to menstruation, the presence of miliary ovisacs in the ovaries, and their appearance beneath the peritoneal coat as small copper-coloured spots, along with others of a yet more minute size, which had penetrated the substance of this membrane, and which did not require more than its thickness for their entire inclusion, together with the protrusion of some of these, often with extremely attenuated coats, in the form of very minute vesicles at the surface of the ovary, or along with puncta, or with a raw, blistered, or abraded appearance; and the existence, at the same time, in either ovary, of a cerebriform body. 31. The changes in the character and mode of the production and discharge of the Graafian vesicles which follow suppressed menstruation, from whatever cause the latter proceeds, was not seen to occur earlier than two months after the last menstrual flow; and previous to the expiry of this period, therefore, there were, in such cases at least as presented only the cephaloid bodies, no indications by which the fact of pregnancy could be determined, irrespective of the discovery of the ovum, and the greater organization of the deciduous fungiform villosities which are thrown out in the uterine cavity at every menstruation, and which, in such cases, suggest the idea of their being the rudimentary spiral arterial coils and horizontal sinuses of the membranous decidua. 34. The only special indication which distinguished the ovaries of lactating women delivered at longer periods than four months after the natural term, was the unusual presence in them of corpora albida. 35. The ovarian condition which most resembles what is here stated as occurring during lactation, is that met with in amenorrhoea from disease. 36. Graafian follicles of some size were found in the ovaries for fifteen, and white bodies for twenty years after the critical age, and the discharge of attenuated minute vesicles, apparently simple cells, from the surface of these glands, appeared to terminate only with life. 37. No relation was found to exist between the number of corpora albida discovered in the ovaries after death and that of the previous pregnancies; nor was there any specific distinction in the ovaries of women who had borne children, as compared with those of females who had not been gravid. 41. The uterine appendages were not, on every occasion, found remarkably injected with blood during or near to the time of the catamenial flow. 47. Ovisacs, containing altered blood, or having their coats dyed black (corpora nigra), or yellow (corpora lutea), may occur independently of menstruation, and were, exclusive of the effusion of lymph from the extremities of the tubes and the exterior of the ovaries, which appeared to have a similar origin, the only ovarian changes which could be suspected to have any connexion with venereal orgasm. REMARKS ON THE EARLY CONDITION AND PROBABLE ORIGIN OF DOUBLE MONSTERS. BY ALLEN THOMSON, M.D. &c. &c. (From the London and Edinburgh Monthly Journal of Medical Science, June, 1844.) In the more important recent works on teratology, though anatomical structure and external form, are made the basis of division into classes, orders and genera, yet the place assigned to a considerable number of malformations in the divisions thus established, is regulated in some measure by the theoretical views entertained of the origin and nature of the malformation, founded upon known laws of embryology. Still even in the best of these classifications Dr. Thomson thinks that sufficient weight has not been given to theoretical considerations of the nature of malformations derived from embryology; and that, by due attention to these views, some improvement may be suggested, at least in the Section comprising malformation by excess. Thus, a careful revision of the various cases of redundant extremities appears to shew that there is not in them, as in most other malformations, a series of gradations from the least to the greatest degree of the abnormal condition, or from the mere superaddition of the joint of a finger to that of a whole extremity; but, on the contrary, that there is a sudden and wide hiatus between the form of polydactyle mal-formation, and the superaddition of a whole extremity. The organs which are usually, if not indeed alone, the seat of an increase in number in single redundant monsters belong to a particular class, those, viz. in which the component parts are naturally numerous, and which are observed to be most subject to undergo variations in number in the series of lower animals. Dr. Thomson is therefore disposed to think it more consistent with observed facts to consider as true double formations only those instances in which the parts of two cerebro-spinal axes, or of two vertebral columns are present, inasmuch as there is, in his opinion, no well-authenticated instance on record of the existence of the double condition of any important organ in which there is not reason to believe, that some degree of duplicity has also existed in the cerebro-spinal system. Dr. Thomson proposes to describe the early condition of double monsters, and to deduce, from a few observations made by himself and others, the most probable theory of their origin. He wishes, however, in the first place, to offer some remarks on the nature of the explanation afforded by a knowledge of embryology regarding the origin and nature of malformations in general. With respect to malformations by defect, almost all teratologists are agreed in referring them to the occurrence of what has been called arrest of development. This theory, however, of arrest of development, is not applicable to all the malformations now under consideration. The various fissures or divisions of organs, as the cleft palate and hare-lip, open processus vaginalis or urachus, &c. are among the best examples of arrested development. But, again, many malformations occurring in single monsters, and all the forms of double malformation, receive little or no direct elucidation from this theory. During a part of the last century much controversy existed among scientific men as to whether mal-formations ought to be considered as dependent on an original tendency, or morbid condition of the germ, or whether they proceeded from injury or disease supervening during development. This controversy has now terminated, according to Dr. Thomson, in too exclusive a rejection of all accidental causes of malformation. Many malformations of the head and spine are with much probability attributable to the occurrence of hydrocephalus or hydrorachitis, at an early period of fœtal life. Various attempts have been made to corroborate the mechanical or accidental theory of the origin of malformations by an appeal to experiments. Though the results of these experiments do not entirely establish the point, still they illustrate in some measure the extent to which some mutilations of the embryo may be indebted for their origin to mechanical causes acting during it's development. It must be admitted, however, that the constancy with which certain forms of malformation return, and the remarkable symmetry they very generally present, deprives this mechanical theory of all its probability, in reference at least to by far the greater number of them, and points to an original disposition of the ovum or germ. (The author promises a continuation of this very interesting article, of which we shall take care to present an analysis.) No. LXXXI. S ON THE CHEMICAL PHENOMENA OF RESPIRATION. By M. GAY-LUSSAC, (Condensed from the Medical Gazette, May 10, 1844.) The physiological world is divided between two opinions on the subject of the chemistry of respiration. According to one, propounded by Black, and advocated by Lavoisier, the formation of carbonic acid and of water takes place in the lungs themselves, and in virtue of the mediate contact of the oxygen of the inspired air with the blood contained in the delicate blood-vessels. According to the other view, the oxygen of the air does not act immediately on the blood in the capillaries of the lungs; it is merely absorbed there: the chemical phenomena in which it is influential take place without the lungs in the course of the general circulation; and it is only on the return of the blood to perform its lesser circuit that it gives off the products of the oxydizing processes that have already taken place in its mass. The latter theory is chiefly indebted to M. Magnus for its development, and for the grounds upon which it was accepted in the world of science. The grand object of Magnus was to prove-1, the presence of carbonic acid in the blood; 2, the different proportions of carbonic acid, and of atmospherical air or oxygen in the blood of the arteries and veins. M. Gay-Lussac questions the validity of M. Magnus' conclusions; some of his inferences being found even in opposition to those which his facts would warrant. According to Magnus' theory, venous should contain more carbonic acid than arterial blood. Yet by actual experiment this chemist obtained less from venous than arterial blood. This grand contradiction, however, is not the only one. Both kinds of blood contain oxygen and azote as well as carbonic acid. If azote be formed in the course of the circulation, as experience has proved, the quantity of this gas ought to be less in arterial than in venous blood. Yet, according to the figures in Magnus' experiments, arterial blood contains half as much azote again as venous blood. The relative proportions of oxygen alone seem at first sight to agree with Magnus' theory, venous blood being found to contain about one-half less oxygen than arterial. Now it is obvious that the carbonic acid which makes its appearance during respiration, is formed at the expense of the oxygen absorbed by the blood; hence there must be a certain relation between the volumes of these two elastic fluids. If, for instance, we know the relative volume of the carbonic acid expired in a given interval, we know that the corresponding volume of oxygen absorbed must be at least equal to it. Unfortunately, the conclusions of M. Magnus regarding the quantities of carbonic acid and of oxygen discovered in arterial and in venous blood respectively, are mutually subversive of each other. For want of positive data, which are not to be attained from the labours of Magnus, we shall take them from Davy. 1. Davy states that a man expires thirteen cubical inches of carbonic acid gas in one minute. 2. That the heart, at each pulse, expels one ounce of blood; and, taking the number of contractions at 75 per minute, 75 ounces, or 115.7 cubic inches of blood, will pass through it in the same interval of time. Now 115.7 cubic inches of blood having given off 13 cubic inches of carbonic acid, 100 of blood will contain 11.23 of this gas, a quantity which the blood might readily part with, as, according to M. Magnus' experiments, it contains much more than 20 per cent. of the gas. But, supposing that the venous blood gave off 11.23 per cent. of its volume of carbonic acid, it is evident that to produce this, arterial blood ought to contain at least an equal volume of oxygen, say 11.23. Moreover, as in the respiratory act, of four parts of oxygen absorbed, three go to form carbonic acid, and one to form water, the blood must have taken up, in its course through the lungs, |