TRANSPLANTATION OF THE VENOM GLAND. 39 



One lobule, which was situated beneath the superficial zone, showed three 

 well-defined areas in which the tubules were in different conditions. In the 

 more superficial area there was a fairly broad cap of clearly defined tubules and 

 acini, in each of which a large lumen was present. These tubules were sepa- 

 rated by thin, fibrous septa, which, however, were much more nearly normal 

 in the superficial part of the zone than in the deeper part, where the fibrous 

 elements were largely necrotic and partly replaced by thin layers of elongated 

 cells. The epithelial lining of the tubules was not entirely normal, the cells 

 showing considerable shrinkage, with loss of clearly defined outlines, in many 

 instances. Each tubule in this zone contained a considerable amount of gran- 

 ular material through which, in some cases, were scattered a few nuclei. 



Below this superficial area came a middle zone of the lobule which was 

 almost entirely occupied by four exceptionally large vesicle-like tubules. 

 These tubules were considerably larger than any of the normal intralobular 

 tubules. They may perhaps have been formed by the fusion of two or several 

 adjoining tubules as the result of the degeneration of the intervening septa and 

 of the desquamation of some of the epithelial elements. Each was lined by a 

 single layer of greatly flattened cells, resembling very much the epithelium of 

 the lung alveoli. These large tubules contained considerable granular matter, 

 in some cases with, in others without, desquamated cells and nuclei. In the 

 largest tubules these desquamated cells were collected into two compact 

 masses, one situated in the center of the lumen, the other to one side, close to a 

 point where the main body of the tubule opened widely into a smaller vesicle. 

 In the case of the latter the origin of such masses by the aggregation of desqua- 

 mated cells was clearly shown, one cell of the mass with its nucleus being 

 observed detaching itself from the epithelial wall. 



The deepest zone of this lobule consisted of several circular or ovoid solid 

 masses of round cells, each mass being separated from its neighbors by a sep- 

 tum formed of rather loose connective tissue. 



In this gland mitotic figures were observed in fair numbers, indicating a 

 rapid proliferation of the cellular elements of the gland. 



Regular, clearly defined secretion granules were not abundant in any of the 

 lobules, even in the almost normal ones near the surface, but they occurred in 

 one or two of the latter, and in the cells of some of the tubules were almost as 

 abundant as in normal cases. 



The lobules in the interior of the gland were largely necrotic, but fre- 

 quently one or several tubules were preserved or were represented by solid 

 cellular masses, similar to those already described. The necrotic material, 

 however, was much less dense than in the transplanted glands already de- 

 scribed, and interspersed amongst it were numerous apparently normal cells, 

 some clearly rounded, others ovoid or spindle-shaped, of connective-tissue 

 origin. We see, therefore, proliferating connective tissue substituting part of 

 the necrotic material. 



