SECRETORY PHENOMENA IN SILK GLAND. 413 



stains (see chart), but occasionally with Altmann's anilin acid 

 fuchsin, methyl green after fixation by the Regaud method, 

 bodies can be found staining deeply green at the periphery and 

 pink in the center. 



(c} Critical. From observations upon silk gland cells of //. 

 cunea, it would seem that the bodies which migrate from the 

 nucleus into the cytoplasm are not nucleoli, but are rather 

 products of nuclear activity. That this is placing too great a 

 burden upon a single small organ of the nucleus may be argued, 

 but it need not necessarily follow that all the products of secretion 

 are derived from the nucleoloid bodies, but rather that the 

 latter contribute bodies which enlarge in the nucleus, pass out 

 into the cytoplasm where they undergo further modification and 

 later become discharged into the lumen. In order to verify the 

 concluding part of this statement, a general survey of the cyto- 

 plasm and its contents is necessary. 



2. The Cytoplasm. 



(a) Cytoplasm. The cytoplasmic structure of the silk gland 

 cell as of any cell, is difficult to describe in concrete terms for 

 it is more or less affected by fixation and the exact or true nature 

 is hard to determine. After fixation with the Champy, Gatenby, 

 Benda, or Regaud methods, the cytoplasm is homogeneous and 

 granular, but after Bouin and Mann-Kopsch fixation, a definitely 

 striated appearance may be distinguished, the striae extending 

 from the lumen toward the periphery. No evidence of fibrils 

 have been found in any case. Yamanouchi ('22) definitely 

 describes fibrillse in the protoplasm between which are situated 

 granules, especially toward the lumen. These, he explains, are 

 cross sections of fibrillae and that the entire structure is composed 

 of minute fibrillae arranged in rows. The usual staining reaction 

 is acidophilic. (See chart.) 



(b) Granules. In the posterior region of the gland, throughout 

 the cytoplasm, there appear spherical bodies either enclosed 

 in vacuoles or apparently free in the protoplasm (Fig. i). 

 Maziarski ('n), Nakahara ('17), and others, noted this condition 

 and from the fact that the bodies are often found in close 

 proximity to the nucleus and exhibit the same staining reactions 



