34 RED BLOOD COEPUSCLES. 



growing tissues. The living particles of the blood 

 vary greatly in size and number, according to the 

 quantity and nature of the food, and a number of 

 circumstances. There exists suspended in the fluid 

 portion of the blood, multitudes of living particles, so 

 minute tliat they cannot be seen by ordinary magni- 

 fying powers. These play a highly important part in 

 the phenomena of the body. I described these minute 

 particles of bioplasm in 1863.* 



52. Red Blood Corpuscles. — Besides the particles of 

 livinof matter, the blood of all vertebrate animals 

 contains multitudes of small, soft, semi-solid particles 

 of a red colour, which give to blood its characteristic 

 appearance. In health, in warm-blooded vertebrata, 

 these are very numerous, and are known as the red 

 Mood corpuscles. The fluid in which these little cor- 

 puscles are suspended is by them as it were much 

 divided, a small portion being smeared over each indi- 

 vidual red blood corpuscle. As these are kept by the 

 propelling power of the heart in continual motion, the 

 equable composition of the blood is maintained, and 

 a small quantity of the fluid portion is smeared upon 

 the wall of the vessel, and upon the bioplasm of the 

 capillary which projects into the cavity, as the red 

 blood corpuscles one after the other are driven into 

 contact with it. So perfect are these arrangements 

 in their working, that iiTegularities in the distribu- 

 tion of the fluid are corrected or compensated while 

 there exists also provision for ensuring that the 

 general composition of the blood shall remain con- 

 stant, in spite of its undergoing most important 

 changes in every part of its course. 



53. Liver for inakliig Bile and altering: the Blood. 

 — The liver, unlike the other important secreting 

 organs developed in the embryo, attains functional im- 

 portance at a very early period of life. Long before 



* " On the Grerminal or Living Matter of the Blood." Trans. 

 Mic. Soc, Dee. 9, 1863. 



