1889-90.J MORPHOLOGY AND PHYSIOLOGY OF THE CELL. 249 



a distinctly marked membrane which, however, may have been only a 

 thickening of the protoplasm bordering the cavity in which the nucleus 

 was situated. 



Not SO common, but still quite readily seen, are forms like that repre- 

 sented in Fig, 5, in which, in place of a single nucleus, there are a large 

 number (over twenty) of safranophilous spherules, each surrounded by a 

 small quantity of finely granular protoplasm and marked off from the 

 rest of the mass by a delicate membrane (Fig. 8^.) These spherules 

 are homogeneous and measure much less than i/x. Fig. 6 apparently 

 represents a later stage of the same body, and in this one sees that 

 the homogeneous spherules have become transformed in such a way, 

 that the stained material in each is arranged in a horseshoe or crescen- 

 tic form, according to the specimen examined (Fig. 6, 7, d>e). The com- 

 parative scarcity of these forms, the very small size of the objects and 

 the absence of a sharply defined contour to the stained material, render 

 it extremely difficult to determine this arrangement satisfactorily in many 

 cases, but in thin and well stained sections, and with good objectives 

 (2mm. immersion apochromatic, Zeiss), forms like those figured appear 

 now and then. 



There can, I think, be no doubt about the parasitic nature of these 

 intracellular bodies, and we may, therefore, regard the stage described 

 in the last paragraph as that of sporulation. 



I endeavored to determine the mode of transition from the stage in 

 which there is a single nucleus to that of sporulation. It was not an 

 easy subject for study, because, for every hundred that one observes 

 belonging to both stages, there are not more than one or two forms that 

 can be ranked as transitional. Two of such are represented in Fig, 

 2>b and c. I have been led to consider them as stages in the formation of 

 spores, because they present structures which resemble somewhat kary- 

 okinetic figures. For example, in the form represented in Fig. d>b, the 

 centrally placed stained body may be regarded as belonging to the 

 dyaster stage and seen from one of the poles ; in it also structures, bear- 

 ing a resemblance to individual chromatin loops, can be made out. This 

 arrangement comes out well sometimes in preparations stained with 

 haematoxylin and safranin, but oftener the safranophilous substance is 

 collected in a ring form resembling, to a certain extent, the equatorial 

 plate of nuclear division. Probably the explanation of Fig. 8^ is 

 that it represents a multiple form of karyokinesis. The difficulty of de- 

 termining the nature of such conditions will be readily understood, 

 when it is remembered that the safranophilous bodies are usually not 2/x 

 in diameter, and that, consequently, its metamorphic elements must be 

 very small. 



