ITS VITAL PROPERTIES^ AND RELATIONS TO LIVING ORGANISM. 199 



Fig. 17. 



dominance of fibrin ; but this idea is far from being correct, since, as will pre- 

 sently appear ( 190), it may result from an opposite condition of the blood. 

 A similar colorless layer is usually observable, when the coagulation of the 

 blood has been retarded by the addition of agents that have the power of delay- 

 ing it ( 184) ; and since, in inflammatory states of the system, the blood is 

 generally long in coagulating, it has been supposed that the separation of the 

 red particles from the fibrinous parts of the clot is due to this cause alone. It 

 was long since pointed out by Dr. Alison, 1 however, that this explanation is in- 

 sufficient, for the two following reasons : "1. The formation of the bufly coat, 

 though no doubt favored or rendered more complete by slow coagulation, is 

 often observed in cases where the coagulation is more rapid than usual , and the 

 coloring matter is usually observed to retire from the surface of the fluid in such 

 cases, before any coagulation has commenced. 2. The separation of the fibrin 

 from the coloring matter in such cases takes place in films of blood, so thin as 

 not to admit of a stratum of the one being laid above the other ; they separate 

 from each other laterally, and the films acquire a speckled or mottled appear- 

 ance, equally characteristic of the state of the blood with the bufly coat itself/' 

 Now we have already seen that the red corpuscles of healthy blood have a 

 tendency to aggregate together in piles and masses ; and it has been pointed 

 out by Prof. H. Nasse 2 and Mr. Wharton Jones, 3 that this tendency is greatly 

 augmented in inflammatory blood (Fig. 17), so that the corpuscles run together 

 into little clumps often visible to the 

 naked eye, and adhere to each other 

 with considerable tenacity. Further, it 

 has been shown by Mr. Gulliver 4 that 

 the subsidence of the red corpuscles is 

 more rapid in inflammatory than it is in 

 healthy blood, and that their rate of sink- 

 ing increases with their aggregation ; so 

 that whilst they sink about an eighth 

 of an inch during the first two or three 

 minutes, they sink through five or six 

 times that space in the next interval of 

 the same length. That the quickness 

 with which they thus aggregate in the 

 lower part of the clot, does not depend 

 (in the case of inflammatory blood) upon 

 the mere facility with which they sink, 

 was further determined by the use of 

 means which tended to diminish or in- 

 crease their aggregation ; thus it was 

 found that the addition of weak saline 

 solutions, by which the liquor sanguinis 

 is attenuated, but which dimmish the 

 mutual attraction of the red corpuscles, 



partially or completely prevented the formation of the bufly coat, in blood which 

 exhibited it strongly when left pure, even though its coagulation was consider- 

 ably retarded thereby j on the other hand, the addition of mucilage with a small 

 quantity of saline matters, the effect of which is to promote the aggregation of 

 the corpuscles, tended to develop the bufly coat by increasing the rate at which 



1 "Outlines of Physiology," 3d edit., p. 89. 



2 "Das Blut," cited in Henle's " Anatomie G&ierale" (traduit par Jourdan), p. 468. 



3 "Report on Inflammation," in "Brit, and For. Med. Rev." vol. xvii. p. 567. 



4 See his Memoir "On the Buffy Coat of the Blood," in the "Edinb. Med. and Surg. 

 Journ." No. 165 ; and his edition of " Hewson's Works," p. 41. 



The microscopic appearance of a drop of Blood in 

 the Inflammatory condition. The red corpuscles lose 

 their circular form, and adhere together ; the white 

 corpuscles remain apart, and are often more abund- 

 ant than usual. 



