vi FORM AND FUNCTION 77 



The duty, almost the sole duty, of the red corpuscles, 

 is to carry oxygen. It is the work of the colourless 

 plasma to bring food to each part and to carry off the 

 used-up material. The carbonic acid, which is pro- 

 duced by the burning of the tissues, is probably 

 removed, not by the corpuscles, but by the fluid 

 in which they float. At the same time the plasma is 

 busy with other work which falls mainly upon it, the 

 work of carrying in all directions the food-materials 

 which have entered the body, and thus what has 

 been destroyed is rebuilt. It is probable that the 

 various components of the blood divide their functions 

 in the way I have described, but it is quite possible 

 that further investigation may show that the foregoing 

 account requires some modification. 



In what part of the body do the corpuscles originate ? 

 In the lymphatic glands corpuscles very similar to, if 

 not identical with, ordinary white corpuscles have 

 been found in process of dividing into two. And it is 

 thought that it is in these glands that the white or 

 colourless kind are produced. 



In embryos, and, on occasion, in adults, the spleen, a 

 small red body which can be found in birds attached to 

 the right side of the fore-stomach (Proventriculus) 

 certainly gives birth to many red corpuscles. In the 

 marrow of human bones corpuscles are found inter- 

 mediate in character between the white and the red, 

 like the former possessing a nucleus, but like the 

 latter having a little of the red haemoglobin, and these 

 it seems are somehow transformed into ordinary red 

 corpuscles. 



