648 EISEiV. [Vol. XV. 



If we now examine these respective zones more in detail, we 

 find that they show characteristics of great constancy. The 

 inner, highly refractive bodies are nearly always well defined, 

 with a very sharp outline. In many are seen concentric layers, 

 though in the majority none such can be recognized, probably 

 on account of the minuteness of the objects. The refractive 

 power is always very great and very striking. These granules 

 vary greatly in size, some being barely perceptible (PL XXXV, 

 Figs. 4, 13); others are so large as to occupy a large part of the 

 blood-plate (PI. XXXV, Figs. 5, 12, 17). The inner, dark- 

 staining mass surrounding these refractive bodies is differenti- 

 ated into several parts, all of which cannot, however, always be 

 shown to be present at the same time. In the center of the 

 mass, generally in close proximity to the refractive bodyj is 

 seen a darker zone with from one to three or even more gran- 

 ules of a yet darker color. This darker zone may be either 

 small or large, sometimes occupying the larger part of the 

 blood-plate (PI. XXXV, Fig. 17); at other times it is confined 

 to the vicinity of the refractive body (PL XXXV, Fig. 18). 



In some blood-plates (PL XXXV, Figs. 6, 12, 13, 16, etc.) 

 the central dark zone contains one or more light areas sur- 

 rounding the darker granules. The minuteness of the blood- 

 plates is such that these, the smallest of the interior structures, 

 lie near the limit of vision, and only the most delicate manip- 

 ulation of the light will show them with any degree of satisfac- 

 tion. There is also a great difference between the individual 

 blood-plates, some being successfully stained, others not. But 

 even in those less differentiated enough can be seen to show 

 that there exists a very remarkable and constant differentiation 

 as regards structure. 



We now come to the outer envelop or zone of the blood- 

 plate. In the toluidine preparations this zone is very faintly 

 stained and barely visible, and the fine filaments can be followed 

 only in isolated instances. With the eosin-hsemalum prepara- 

 tions the case is different ; here the filaments are distinctly 

 stained, sometimes even intensely brought into view, but there 

 is less differentiation of detail. In the blood-plate stained with 

 toluidine we can often see a slight differentiation of this outer 



