CHAP. vii.J THE CAT'S ORGANS OF CIRCULATION. 195 



and as fully shares in the body's vitality as do the other tissues. 

 The corpuscles may be regarded as answering to those nucleated 

 cells which we have found to exist in the other tissues, while the 

 liquor sanguinis corresponds with the matrix of such other tissues 

 the matrix being fluid in the blood tissue, instead of being calcareous, 

 as is bone, chondrified as in cartilage, or more or less fibrous as in 

 connective tissue. 



As has been already mentioned, the blood may appear either 

 scarlet or purple, and from the relation of blood so diversely coloured 

 to the parts which contain it, these two kinds of blood are spoken of 



Fig. 99. BLOOD CORPUSCLES OF MAN AND OF THE CAT, SIMILARLY ENLARGED. 



A. Blood corpuscles of man. 



B. Blood, corpuscles of the cat. 

 a. Red corpuscles. 



1). A single one seen edgeways. 



c. A few grouped in a pile. 



d. Normal white corpuscles. 



e. A white corpuscle treated with acetic acid 



and showing its nucleus. 

 /. One slightly altered. 

 fj. A white corpuscle in the act of changing its 



shape by amcebiform movement. 



respectively as ARTERIAL and VENOUS. The scarlet or arterial 

 blood is found (1) in the arteries or vessels Avhich carry blood from 

 the heart as well as (2) in vessels which proceed from the lungs. 

 The purple or venous blood is found (1) in the veins generally, (2) 

 in certain vessels ramifying in the liver, and (3) in others proceeding 

 to the lungs. 



The difference between arterial and venous blood depends upon 

 arterial blood containing a greater quantity of oxygen, and venous 

 blood possessing more carbonic acid. Blood contains a large amount 

 of gas (about half its own volume), principally the gases just 

 named, but also some nitrogen, introduced within it probably by the 

 lungs. 



3. LYMPH is a slightly alkaline, clear, colourless, or pale yellow 

 fluid, containing only 5 per cent., by weight, of solid constituents. 

 It is thinner than blood, but, like it, contains albumen, some salts, 

 and some extractive matters. It is devoid of red corpuscles, 

 being in fact like the liquor sanguinis, and being, like it, capable of 

 coagulation. It is in fact (as before said) made of the exudation of 

 the liquor sanguinis mixed with fluid absorbed from the alimentary 

 canal. Its likeness to blood is the more complete, since it contains 

 numerous colourless corpuscles, " lymph corpuscles" and which are 



quite like the colourless corpuscles of the blood. 



o 2 



