746 



NUTRITION. 



rous as the red particles : this, Mr. Gulliver 

 has frequently noticed in foetal deer of about 

 an inch and a half long. In a still smaller foetus 

 the blood was pale from the preponderance of 

 the white corpuscles. It is, therefore, a fact of 

 much interest that, even in the mammiferous 

 embryo, at the period when growth is most 

 rapid, the circulating fluid has a strong analogy 

 to that of the Invertebrata. It then, too, bears 

 in other respects the most striking analogy to 

 chyle ; since it consists of the fluid elaborated 

 from the organizable matter supplied by the 

 parent, and directly introduced into the current 

 of the circulation. The function of the placenta! 

 vessels may be regarded as double ; for they 

 are at the same time the channel, through which 

 the alimentary materials supplied by the pa- 

 rent are introduced into the circulating system 

 of the foetus, and the medium of aerating the 

 fluid which has traversed the fcetal system. 

 Hence the placenta may be regarded as at 

 once the digestive and the respiratory appa- 

 ratus of the foetus, and the fluid circulating 

 through the cord as at once chyle and blood. 

 It is not until the pulmonary and lacteal vessels 

 of the embryo have commenced their indepen- 

 dent operation, that the distinction between the 

 blood and the chyle of the foetus becomes evi- 

 dent; and we should expect, therefore, to find 

 that the circulating fluid, up to the time of 

 birth, contains a large proportion of white cor- 

 puscles, which is actually the case. There is a 

 gradual decrease, however, in their proportional 

 number, from the earlier to the later stages of 

 embryonic life, in accordance with the dimi- 

 nishing energy of the formative processes. It 

 has been also observed by Wagner* that the 

 number of colourless corpuscles is always re- 

 markably great in the blood of well-fed frogs 

 just caught in the summer season ; and that it 

 is very small in those, which had been kept long 

 without food, and in those examined during the 

 winter. 



The most remarkable evidence, however, of 

 the connection between the generation of white 

 corpuscles in the blood, and the production of 

 fibrin, is derived from the phenomena of in- 

 flammation. A decided increase in the normal 

 proportion of fibrin in the blood (from 2- to 

 85 parts in 1000) may probably be looked 

 upon as the essential indication of the existence 

 of the inflammatory condition. For it appears 

 from the observations of Andral and Gavarret 

 (\\hich have been confirmed by many other 

 pathologists) that such an increase uniformly 

 manifests itself, when a local inflammation com- 

 mences, even when the proportion of fibrin 

 has previously been abnormally lo%v, as in 

 febrile diseases ; that it bears a constant rela- 

 tion with the extent and intensity of the diseased 

 action ; and that it diminishes with the abate- 

 ment of the morbid condition of the part affected. 

 In some instances, the proportion of fibrin was 

 seen to rise as high as 9 or even 10 parts in 

 1000; but an increase to the amount of 6, 7, 

 8 parts, was more common. That this pro- 

 duction of fibrin is due to a local change can 



* Op. cit. p. 245. 



scarcely be doubted ; since it is frequently 

 observed to commence before any consti- 

 tutional symptoms manifest themselves ; and it 

 may be regarded, in fact, as one cause of these 

 symptoms. Now the recent microscopic ob- 

 servations of Mr. Addison* and Dr. Williams,f 

 which were made independently of each other, 

 have established the important fact, that a 

 great accumulation of white corpuscles takes 

 place in the vessels of an inflamed part ; and 

 this seems to be caused at first by a deter- 

 mination of those already existing in the circu- 

 lating fluid, towards the affected spot; but 

 partly by an actual increase or generation of 

 these bodies, which appear to have the power 

 of very rapidly multiplying themselves. The 

 accumulation of white corpuscles may be easily 

 seen, by applying irritants to the web of a frog's 

 foot. Mr. Addison has noticed it, in the 

 human subject, in blood drawn by the prick 

 of a needle, from an inflamed pimple, the base 

 of a boil, the skin in scarlatina, &c. And 

 the writer, without any knowledge of these 

 observations, had remarked a very obvious 

 difference between the proportions of white 

 corpuscles, in blood drawn from a wound in 

 the skin of a frog immediately upon the incision 

 being made, and in that drawn a few minutes 

 after ; and had been led, like the observers 

 just quoted, to refer this difference to a deter- 

 mination of white corpuscles to a part irritated. 

 The absolute increase, sometimes to a very con- 

 siderable amount, in the quantity of white 

 corpuscles in the blood of an inflamed subject, 

 has been verified by Mr. Gulliver and several 

 other observers. These facts, therefore, afford 

 strong ground for the belief, that the production 

 of fibrin in the blood is closely connected with 

 the development of the white corpuscles; and 

 when we consider them in connection with the 

 facts previously urged, there scarcely appears to 

 be a reasonable doubt, that the elaboration of 

 fibrin is a consequence of this form of cell-life, 

 and is, in fact, its express object. 



A recent observation of Mr. Addison's, more- 

 over, would seem to indicate, that no inconsider- 

 able proportion of the fibrin of the circulating 

 blood is contained within the white corpuscles. 

 " Provide six or eight slips of glass, such as are 

 usually employed for mounting microscopical 

 objects ; and as many smaller pieces. Having 

 drawn blood from a person with rheumatic 

 fever, or any other inflammatory disease, place 

 a drop of the colourless liquor sanguiuis, before 

 it fibnllates, on each of the large slips of glass; 

 cover one immediately with one of the smaller 

 slips, and the others one after another at inter- 

 vals of thirty or forty seconds, : then, on 

 examining them by the microscope, the, first 

 will exhibit colourless blood corpuscles in 

 various conditions, and numerous white mole- 

 cules distributed through a more or less copious 

 fibrous network ; and the. last will be a tough, 

 coherent, and very elastic membrane, which 

 cannot be broken to pieces nor resolved into 



* Medical Gazette, Dec. 1840 ; Jan. and March, 

 1841. 



t Medical Gazette, July, 1841 ; aud Principles 

 of Medicine, pp. 209, 210.' 



