168 



COMPARATIVE PHYSIOLOGY. 



The excessive action of these organs results in the production 

 and discharge into the blood-current of cells that are immature 

 and embryonic in character. This seems to us an example of 



Oaa 



Fig. 153. 



Fig. 149. — Outlines of red corijuscles in a caBe of profound anaemia. 1, 1, normal cor- 

 puscles; 3, large red corpuscle — megalocyte; 3, 3, very irregular forms — ^poikilo- 

 cytes; 4, very small, deep-red corpuscles— microcytes. 



Fia. 150.— Origin of microcytes from red corpuscles by process of budding and fission. 

 Specimen from red marrow. 



Fi«. 151. — Nucleated red blood-corpuscles from blood in case of leukeemia. 



Fig. 158.— Corpuscles containing red blood-corpuscles. 1, from blood of cbild at term; 

 3, from blood of a leuksemic patient. 



Fie. 153.— a, 1, 2, 3, spleen-cells containing red blood-corpuscles, b, from marrow; 1, 

 cell containing nme red corpuscles; 2, cell with reddish granular pigment; 3, fusi- 

 form cell containing a single red corpuscle, c, connective-tissue corpuscle from 

 subcutaneous tissue of young rat, showing the inti'acellular development of red 

 blood-corpuscles. (Pigs. 149-153, after Osier.) 



a reversion to an earlier condition. It is instructive also in that 

 the facts point to a possible seat of origin of the cells in the 

 adult, and, taken in connection with other facts, we may say, to 

 their normal source. These blood-producing organs, having 

 too much to do in disease, do their work badly — it is incom- 

 plete. 



Although the evidence, from experiment, to show that the 



