ANATOMY OF THE POISON GLAND OF HELODERMA. 



25 



shows what I interpret as an alveolar or foam structure, the c^ear spaces or 

 vacuoles being quite large and conspicuous, with only very thin strands of 

 cytoplasm separating them. In these vacuoles lie the fully formed granules, 

 typically a single granule to each vacuole. The granules, like those of serous 

 glands generally, are characterized by their large size, definite form, and the 

 avidity with which they absorb such stains as iron hematoxylin and gentian 

 violet. In some cases the cells are so numerous and so densely crowded within 

 the cell that they quite obscure the alveolar structure of its protoplasm. In 

 other cases they are much less numerous and may be entirely absent. A feat- 





FIG. 10. Section passing through point of union of two intralobular ducts, showing granule-secreting epithelium. 



Normal gland (Zeiss oc. 2, obj. T ' 2 ). 



ure which has also been noted in other glands is that while all or nearly all of 

 the intralobular cells of a single lobule contain numerous granules, those of 

 neighboring lobules may show few or no granules. 



The mode of formation of the secretory granules appears to me to conform 

 to the mode observed by E. Muller (Archiv f. Anat. u. Physiol., 1896, S. 317 ff, 

 cited from Metzner in Nagel's Lehrbuch der Physiologic, 1907). Minute, 

 dark-staining particles appear in the nodes of the cytoplasmic ( = spongio- 

 plasmic) reticulum. These apparently increase in size and definiteness and 



