162 THE PRACTICE OF VETERINARY MEDICINE. 



capillaries are very delicate and minute in size. The blood 

 is red in colour, saline in taste, and consists of solid and 

 fluid portions. The corpuscles^ white and red, form the solid 

 portion of the blood, and the liquor sanguinis forms the 

 fluid portion of the blood. The red corpuscles are found 

 chiefly in the centre of the circulating stream, and the 

 white are found on the edges of the stream, clinging to the 

 walls of the vessels, and occasionally passing through by 

 osmosis. The corpuscles exist in the proportion of three 

 or four of the white to one thousand of the red. The tem- 

 perature of the blood is usually about 100° F. It is homo- 

 geneous when first drawn from the body, but soon loses 

 this condition, separating into a crassamentum, or clot, and 

 a serous or fluid portion. The red corpuscles are disc- 

 shaped, and slightly smaller than the Avhite corpuscles, 

 which are of irregular outline, and have the power of 

 changing their sha^^e. When the red corpuscles become 

 altered in shape, it is always on account of the presence of 

 disease. The chemical composition of blood is as follows : 

 water, 784 ; albumen, 70 ; fibrin, 3 ; alkaline and neutral 

 salts, 8-5 ; corpuscles, 127 ; other substances, 7 "5 ; total, 

 1,000 parts. Water is a very important constituent of 

 blood, as by it a proper degree of fluidity is preserved. 

 Albumen is also very important, being derived from the 

 chyle, and constituting the concentrated nutriment of the 

 chyle. In speaking of certain conditions of the blood we 

 say there is an excess of fibrin, or too small a quantity of 

 fibrin. Blood possesses the property of spontaneous coagu- 

 lation by virtue of the fibrin which it contains ; and, when 

 haemorrhage occurs, it is the fibrin which causes it to stop. 

 When fibrin does not exist in sufficient quantities, as in 

 some diseases — purpura, for instance — haemorrhage is likely 

 to be fatal. The amount of blood in an animal varies from 

 one-eighteenth to one-twentieth of the total weight of the 



