106 ANIMAL PHYSIOLOGY. 



less tinged with red. If, while the blood is flowing, in bleed- 

 ing from the arm, the physician whips or rapidly stirs it with 

 a bunch of small rods, as sometimes used to be done, the fibrin 

 will adhere in tough coagulated masses to the rods, and the 

 remainder of the blood will remain fluid. This defibrinated 

 blood, after a while, will separate into clear serum above, and 

 a dark dense portion below. An examination of blood under 

 the microscope shows it to consist of a clear fluid with a 

 multitude of coloured corpuscles floating in it; and the 

 separation of the defibrinated blood into two parts, is the 

 result of these corpuscles falling to the bottom of the liquid 

 serum. If blood be taken from a person in certain, exceptional 

 conditions, or if it be taken from a horse, instead of the 

 whole mass becoming converted 



cor P usc ^ es w iU subside consider- 

 ably before coagulation sets in, 

 and then there will be in the upper 

 part of the vessel a straw-coloured 

 coagulum forming a transparent 



J ell 7- Tnat is a state of Batters 

 which formerly medical practition- 

 ers considered as a certain sign of 

 inflammation, and described by 

 saying that the blood was 'buffed. 

 Fig. 60. HUMAN BLOOD Con- The clear coagulum in contracting 

 PUSCLES. a, a, Bed cor- becomes loosened from the edge 



, 



puscles of smaller size, such upper surface, while a pure serum 

 as are now and then seen is pressed out at the sides and 

 exceptionally; c, c, red cor- nto t ^ e con cavity above : and this 

 LTt S 1o e w?f tf^d <*edd practitioners expressed by 

 corpuscles shrivelled by saying that the blood was cupped. 

 partial evaporation of the These observations furnish a 

 serum; e, a red corpuscle r0 ngh but instructive analysis of 



jr^/SftSSS ^ ? ree cons f ue are ex - 



puscles; g, one which has hibited, the corpuscles, the serum, 



undergone amoeboid change and the fibrin. The serum and 



of form. ,^ , fibrin together constitute the liquor 



sanguinis, or blood plasma. The blood may thus be separ- 



