638 E/SEN. [Vol. XV. 



plates as they appear under a narrow angle lens and without 

 staining. His figure shows the plates, or, as he calls them, 

 " Plaques " and " Kornchenbildungen," to be simply minute 

 globules of various size, with smooth outlines, although in the 

 text of the paper he mentions that they frequently show fine 

 filaments projecting in all directions, which he contends are 

 nothing but fibrin threads. As to the nature of the "Plaques," 

 Schultze hints at two possible views. Either they may be 

 elementary parts capable of development, or they are simply 

 " Detritusbildungen " or debris. In order not to prejudice any 

 one in favor of the one or the other of these views, he selects 

 for these bodies the name " Kornchenbildungen " as least com- 

 promising. Schultze refers also to other granulations in the 

 blood, previously described by Kolliker, H. Miiller, Zimmerman, 

 Hensen, Virchow, and others ; but I think it of minor impor- 

 tance to decide whether these investigators observed the true 

 blood-plates or simply had before them artifacts or ddbris. 



Bizzozero has, undoubtedly, next after Schultze, contributed 

 most to our knowledge of the blood-plates. In a paper pub- 

 lished almost twenty years after Schultze, he describes the 

 blood-plates as a new and independent element of the blood, 

 and one to which he assigns a most important function, — that 

 of causing coagulation of the blood. Since the first researches 

 of Bizzozero several investigators have taken up the study of 

 these minute bodies, especially as regards their origin and 

 functions. The structure and inner organization of the plates 

 have, however, hardly been touched upon, and the discussions 

 have mainly turned on the point of whether the plates are 

 preformed in the blood, or whether they consist simply of 

 chemico-mechanical precipitates or degenerations. To these 

 respective views I can here only briefly refer. 



Bizzozero contends that the blood-plates are preformed in 

 the blood, and that they supply material for the fibrin. Hayem, 

 who has studied this subject minutely, not only supposes that 

 the blood-plates, to which he gives the name " hsematoblasts," 

 are preformed in the blood, but considers them to be erythro- 

 cytes, or, in other words, he believes that in time they develop 

 into perfect red blood-corpuscles. His theory has, however, 



