42 THE VENOM OP HELODEEMA. 



consisted of apparently normal tissue aggregated into acini and tubules, each 

 with a clear and distinct lumen, the latter usually containing more or less 

 granular and desquamated material. The cells in general were regular in size, 

 structure, and contents. The typical secretion granules were mostly absent, 

 but in one lobule they were observed in profusion, the cells in which they 

 were found having the appearance of normal intralobular duct-cells. In the 

 deeper portions of the peripheral zone the cells were not so regular and the 

 lumina of the tubules were less distinct. The interior of the piece con.sisted 

 entirely of necrotic material. 



Experiment D. — Gland Removed Foue Weeks after Transplantation. 



The gland used in this experiment was obtained from individual IM on 

 May 31 and was transplanted to the left thorax of individual N. There it 

 remained until June 28, when it was removed and fixed in Kopsch fluid. A 

 small piece of it was at the same time used to inject a mouse, which died 

 shortly afterwards. The most prominent feature shown by this gland was 

 an extensive proliferation of small round cells, either of connective-tissue 

 origin, or leucocytes emigrated from the blood-vessels. These cells were 

 exceedingly abundant about the periphery of the gland, where they formed a 

 dense layer of considerable average thickness. Beneath this layer was a zone, 

 not very thick, of gland-tissue, which, however, was in most lobules not 

 entirely normal. In one or two lobules some of the acini seemed to be entirely 

 normal, each mth a clear lumen, but usually the cells were more or less 

 shrunken, while the lumina were either indistinct or filled with desquamated 

 cells or disintegrated material. Here and there in these same lobules some 

 of the larger tubules showed a distinct lumen, but the cells lining it were much 

 more flattened than in normal cases. 



The small round cells mentioned above extended into the lobules along 

 the septa. The latter showed only slight traces of fibrous tissue, and were 

 almost entirely composed of strands of round cells. In the deeper layers of 

 the transplanted piece, where the acini were mostly pycnotic, the round cells 

 spread out beneath the lobule, frequently forming dense masses aggregated 

 about the dying gland-cells or congested blood-vessels. From these points the 

 small cells were found to radiate into the subjacent necrotic areas. 



The necrotic region of the transplanted piece was very extensive. Com- 

 pared with the same region in the transplanted pieces removed at an earlier 

 period, it was distinguished by a great reduction in the amount of actual 

 necrotic material. In the earlier stages the latter was so abundant as to make 

 the necrotic regions more or less strongly opaque. In the present gland, on 

 the other hand, the actual quantity of purely necrotic material was small, 

 the entire region consisting almost exclusively of a loose fibrous tissue, with 

 large, clear interspaces and numerous widely scattered round cells. 



In a few places the round cells were observed to form dense strands 

 extending from the periphery into the necrotic portions. Usually, however, 

 the infiltration appeared to be irregular, the cells dispersing in all directions 

 from the aggregations at the base of the lobules. 



None of the typical secretion granules were observed in this gland. 



