RKVIEWS. 299 



they may be transitional forms between the white and the 

 red globules, or that they may be a stage in the retrograde 

 metamorphosis of the red globules. The former supposition 

 is obviously untenable, since forms intermediate between 

 white and red corpuscles are known, and are different from 

 microcytes ; and it seems, therefore, more probable that 

 microcytes are atrophic forms, that is to say, red corpuscles 

 which are in course of destruction, the more so as the artifi- 

 cial destruction of red corpuscles by heat, pressure, or desic- 

 cation, produces very analogous forms. Thus, the white 

 corpuscles would come to represent the infancy of the blood- 

 elements, the red corpuscles their adult stage, and microcytes 

 the period of old age. 



The cause of so grave an alteration of the red corpuscles 

 remains still obscure, but the spleen and liver both suggest 

 themselves as possible seats of the change. Among many 

 conflicting opinions as to the function of the spleen, several 

 authorities ag^ree in attributing to it a destructive action on 

 the red globules, while a more general consensus of opinion 

 ascribes the same function to the liver. The theory which 

 the authors found upon the case observed by them is as 

 follows : — That the spleen, though not destroying the red 

 corpuscles, alters them and prepares them for destruction, 

 converts them, that is to say, into microcytes, which are 

 further destroyed in the liver, though in neither place does 

 the change affect more than a small proportion of the 

 corpuscles. 



Supposing that the spleen should undergo hypertrophy, 

 and its action on the blood-corpuscles be proportionally inten- 

 sified, the number of microcytes sent into the circulation by 

 the splenic vein will be proportionally increased ; and this 

 increase will be greater still if there should be a simultaneous 

 atrophy, that is to say, diminished action of the liver, which 

 would thus destroy a smaller number of microcytes. The 

 proportion of these in the blood might then become quite 

 enormous. This theory is thought to explain more simply 

 than any other the fact that the composition of the blood re- 

 mains almost unaltered after the extirpation of the spleen. 

 If, normally, the only action of the spleen on the blood is to 

 produce microcytes, and the normal function of the liver be 

 to destroy them, while the latter organ remains sound the 

 blood will not betray by its composition whether the number 

 of microcytes formed be large, small, or actually none at all, 

 that is to say, whether the action of the spleen be vigorous, 

 feeble, or 7iil. 



