204 Dr. Anderson on the state in which Fibrin exists in the Blood. 



How the corpuscles of serous effusions are formed we cannot yet 

 surely say : not, probably, as Dr. Addison * supposes, by the 

 actual passage through the walls of the capillaries of the white cor- 

 puscles of the blood. The simplest effusion which takes place from 

 vessels is pure water, as from the Malpighian bodies of the kidneys.t 

 When there is more pressure or excitement, serum is effused, being 

 water with albumen in solution, as in dropsy, or renal congestion 4 if 

 the local excitement still increase, fibrin is thrown out, and coagulates 

 spontaneously when withdrawn from the body, as in the fluid of 

 blisters ; § and a yet higher action of the part results in the tlirow- 

 ing out of " lymph," or coagulable matter full of active cells, which, 

 as in the inflammations of serous membranes, becomes rapidly 

 organized. Dr. Addison would say that these cells are the white 

 corpuscles of the blood, which have traversed the coats of the 

 vessels, and go to form the plastic fibrin of the effusion ; but then 

 its plasticity ought to be in the ratio of their number, which is noto- 

 riously not the case : for pus, the most aplastic of all effusions, actually 

 swarms with distinct corpuscles, very like those found in the blood, 

 and yet contains no coagulating fibrin at all. 



The opinion of Gendrin,|| that the pus corpuscle is formed from 

 the red blood globule, can scarcely now be held, except it be by Dr. 

 M. Barry ; and it is extremely improbable that bodies such as the 

 white corpuscles, which are larger than the red globules of the blood, 

 as l-2600th to l-3500th of an inch, should traverse the unruptured 

 capillary walls while the latter are retained. 



The nutrition of nonvascular tissue is effected^ by the transu- 

 dation of nutritive matter through the coats of the looped capillaries 

 which encroach upon its edges ; and we cannot suppose that white 

 corpuscles, even if they too transuded, should make their way 

 onwards to the centre of a solid mass of cartilage, for instance: we 

 must suppose that it is the plasma alone which the tissue imbibes, 

 and by which its living cells are nourished ; and so in the case of 

 effusion it seems most probable that what really occurs is simply 

 a transudation of that plasma, nourished by which the corpuscles 

 grow, whether they be descended from "germinal granules," or *'cy- 

 toblasts," or in whatever way they originate. 



The " molecules " and " granules," formed so abundantly in the 

 buffy coat, exist also in healthy blood, in the serum of whicli they can 

 be seen by the microscope ; and in " milky" serum, such as occurs in 

 renal inflammation, they are very abundant. Simon has shown tt 

 that it is in part to an albuminous, and not, as Prout and ChristisonH 

 supposed, wholly to a fatty matter that such serum owes its opacity ; 

 and by the microscope it can be seen to swarm with particles resem- 



* Loc. Cit. t Bowman, Phil. Trans. 1842. X Robinson, Med. Chir. Trans. 1843. 



§ Dr. Buchanan, loc. cit. p. 133. || Sur les Inflam. ii. 472. 



** Toynbee, Phil. Trans. 1842. ft Beitraege, <fee. Lief. 1. 



XX On Granular Degen. of the Kidney. 



