No. 3.] BLOOD-PLATES OF THE HUMAN BLOOD. 639 



not found many adherents, as it is readily demonstrated that 

 we do not find in the blood any transition forms between 

 blood-plates and erythrocytes. 



On the other hand, a large number of investigators hold that 

 the blood-plates originate from the breaking up of the leuco- 

 cytes, or that they are in some way altered leucocytes. This 

 view is taken by such biologists as A. Mosso, Ries, Halla, 

 Griesebach, Weigert, Botkin, Lilienfeld, Hlava, and others. 

 Among these, A. Mosso considers the blood-plates to be altered 

 leucocytes, while Lilienfeld and Hlava claim that they consist 

 mainly of nuclein derived from broken-up nuclei, on which 

 account these investigators suggest the name " nuclein-plates." 



Hayem, already referred to, must be counted in the above 

 group, as he supposes that the blood-plates originate in the 

 protoplasma of the leucocytes and are projected out from the 

 latter before they enter into the circulation of the blood. 



Casimiro Mondino and Luigi Sala compare the blood-plates 

 to the fusiform corpuscles of batrachian, reptilian, and bird 

 blood ; views adopted by nearly all succeeding investigators. 



We now come to a large group of investigators, who are of the 

 opinion that the blood-plates are in some way derived from the 

 red corpuscles (the erythrocytes) of the blood. Among these 

 observers we count Klebs, Ponfick, Welte, Bremer, Wlassow, 

 and Prof J. Arnold of Heidelberg, than whom none stand 

 higher, and whose investigations are worthy of the highest 

 consideration. Arnold's earliest investigations were made on 

 blood treated with iodide of potassium, or with normal salt 

 solutions (0.6 per cent.). He found that erythrocytes thus 

 treated disintegrate in various ways, and that the fragments 

 greatly resemble blood-plates. But as through this method 

 only a probability in the result was reached, new investiga- 

 tions were made on living blood in the mesenterium of the 

 mouse, also with the addition of normal salt solution. Arnold 

 thus found that the erythrocytes show minute wart-like or 

 globular elevations or buds, which latter separate themselves 

 from the mother erythrocytes ; or some erythrocytes assume 

 a mulberry form, the minute globules of which either separate 

 singly or in mass. The separated globules differ greatly in 



