30 EISEN. [Vol. XVII. 



in their interior several highly refractive bodies which I have 

 termed " endochromatic granules." These granules never occur 

 in the true nucleoli, which fact always enables us to distinguish 

 between them and the chromoplasts, even in instances when 

 the true nucleoli are stained darkly, as sometimes happens. 

 The endochromatic granules never stain, but appear to be 

 naturally of a yellowish color and always highly refractive. 

 They vary in size, and are sometimes so small that their refrac- 

 tivity is not readily perceived, they appearing only as minute 

 granules of an intensely dark color. But as they increase in 

 size we begin to see in their center a light-colored, highly bril- 

 liant spot, which, in the larger granules, is correspondingly 

 large and distinct. These refractive granules are almost invari- 

 ably present, and they may be truly termed "landmarks," by 

 which we can determine the position of the chromoplast. 



Even in places where the chromoplast itself cannot be dis- 

 tinguished we can judge of its presence by one or more of these 

 endochromatic granules, as, for instance, in the metaphase and 

 anaphase of the auxocytes. It is the presence of these gran- 

 ules which enables us to follow with certainty the evolution of 

 the chromoplasts, and to ascertain their presence in every stage 

 of the nucleus. The number of granules in each chrorfioplast 

 is in no way constant and seems to be of no great consequence. 

 Some are perfectly round, others are angular, and their general 

 appearance seems to indicate that they constitute secreted 

 matter, or metabolic products, probably for the attraction and 

 nourishment of the chromioles. While each granule is highly 

 refractive in the center, its outline is, on the contrary, very dark, 

 so dark indeed that it would almost seem as if it was surrounded 

 by a shell of some particular substance. Whether that is the 

 case, or whether the dark margin is only the effect of refraction, 

 I have not been able to ascertain. In the small chromoplasts 

 attached to the chromosomes in the metaphase we sometimes 

 find one or two endochromatic granules, sometimes also none. 

 In the confluent umbrella stage of the nucleus we generally 

 find a larger number of granules which appear to have been 

 newly secreted. They disappear at the end of the umbrella 

 stage, though a few may remain even after the nucleus has 



