656 EISEN. [Vol. XV. 



Such great length must be in certain respects a disadvantage 

 to the free circulation of the cells, which if turned sideways must 

 necessarily be impeded in their travel. If, however, the poles 

 could be loaded and increased in weight, the cells would be more 

 apt to travel with their pointed ends forward, and their speed 

 would thus be increased instead of retarded. I believe the func- 

 tion of the globules is to thus load the poles of the cells and 

 keep their pointed ends forward instead of sideways. This 

 opinion is strengthened by the fact that the rounder erythro- 

 cytes possess no such directing globules. 



XV. Summary. 



1. We must distinguish between true and false blood-plates, 

 and between organized and non-organized blood-plates. The 

 only true blood-plates are those of plasmocytic nature. The false 

 blood-plates are either fusiform corpuscles, degenerating frag- 

 ments of leucocytes and erythrocytes, or chemico-mechanical 

 precipitations of fibrin and globulin. 



2. In the blood of Batrachoseps the organized blood-plates 

 are of two kinds, fusiform corpuscles and plasmocytes, the 

 latter derived from the former. In the blood of many other 

 batrachians and reptilia the organized blood-plates are only 

 fusiform corpuscles, no plasmocytes being found. 



3. In the human blood the true blood-plates are true plasmo- 

 cytes, possessing the same general nature and structure as 

 those in the blood of Batrachoseps. In these blood-plates in 

 the human blood we may distinguish various zones and spheres. 

 These are : 



a. Three outer cytoplasmic spheres : cytosphere, hyalosphere, andgrano- 



sphere. 



b. Three inner spheres : centrosphere, somosphere, and centrosomes. 



c. A centrally or laterally situated, highly refractive granule, which may 



be either a food granule, or a secreted product, perhaps a fer- 

 ment causing the coagulation of the blood. All the true blood- 

 plates of the human blood have this structure. 



4. In the human blood, under certain conditions, there may 

 also be found false blood-plates, caused by precipitation of glob- 



