TRANSPLANTATION OF THE VENOM GLAND. 37 



toward the other they were necrotic. A few lobules near the center were inter- 

 mediate, being in part necrotic, in part consisting of normal gland-tissue. 



In the living lobules the cells were in general large and quite irregular, 

 differing in no visible respect from normal gland-cells. In most of the living- 

 lobules the cells appeared in good condition; in some, especially those near 

 the center, a narrow zone of pycnotic cells intervened between the living cells 

 and the necrotic mass. In many of the lobules the tubules and acini showed 

 a large and distinct lumen which contained a mass of more or less translucent 

 particles and numerous desquamating cells or cell-groups. 



The cytoplasm in the living cells was moderately dense and finely reticu- 

 late with minute granules. But no typical secretion granules were found in 

 them. 



In some acini indistinct mitotic figures were observed, but were very scarce. 



In the intermediate zones there were numerous dying cells. Some of the 

 cells were apparently living, but showed no distinct outlines or regular struc- 

 ture. Other cells were entirely vacuolar, owing to liquefaction of their con- 

 tents. Many of their nuclei were large and vesicular, with an almost colorless 

 ground-substance and scattered chromatin knots. 



In the necrotic portion of the gland were observed numerous connective- 

 tissue cells apparently invading it from all directions. Their nuclei were rather 

 regular in outline, sometimes rounded, sometimes elongated, and occasionally 

 constricted on one side. Each showed a clear ground-substance through which 

 were scattered numerous fine chromatin particles, while part of the chromatin 

 was aggregated near the center into a conspicuous nucleolus-like mass. 



Experiment D. Gland Removed Four Weeks after Transplantation. 



A fourth animal (N) was operated upon on May 31. A portion of its 

 right gland was removed and divided into two pieces. One piece, N 1 , was 

 then transplanted to the right thorax of N; the other, M 2 , was transplanted 

 to the left thorax of M. The gland N 1 was removed June 28 and fixed in 

 Kopsch fluid. A part of it was transplanted to a mouse, which died after a 

 few days. 



This piece of gland was more nearly like the normal gland than any of the 

 other transplanted pieces removed at earlier periods. The peripheral lobules 

 were all quite normal in appearance. Thus in one lobule selected for study 

 the terminal acini were to all appearances quite normal and constituted the 

 bulk of the lobule. Each acinus was separated from adjacent acini by clear 

 fibrous septa, similar to those separating normal acini. The cells were typical 

 in form and contained an alveolar cytoplasm in which coarse granulations were 

 present at the nodes of the reticulum. The nuclei were situated close to the 

 basement-membrane, and in many cases were rather more shrunken than normal 

 nuclei. This shrunken condition was not, however, pronounced, while in other 

 cases the nuclei were apparently quite normal. Each nucleus contained a 

 clear nuclear sap in which were scattered grains of chromatin and a central 

 chromatin knot, the entire chromatin arrangement being essentially like that 



