TRANSPLANTATION OF THE VENOM GLAND. 43 



Series III. 



In Series III portions of those glands from which the pieces transplanted 

 in the preceding experiments had been cut were examined. They were used 

 partly as control and partly to determine whether regeneration of the excised 

 portions took place. For the latter purpose the sections were made at right 

 angles to the superficial blood-clot which filled the cavity produced by the 

 excision. Examination of the sections showed the glands to be normal in every 

 respect. No sign of regeneration of the missing parts of the gland was observed. 

 Measurements of the cells showed that no perceptible shrinkage or hypertrophy 

 had taken place. 



Series IV. 



In Series IV pieces taken from the normal, uninjured gland of the animals 

 in which the gland of the other side had been partly excised were examined. 

 They were used as controls. These glands were perfectlj^ normal in every 

 respect. Typical cells were measured and were found to have the average 

 size of cells of glands taken from animals that had never been operated upon. 



Series V. 



Only one experiment was made in Series V. A part of a normal gland, 

 taken from Gila monster N, was transplanted to a turtle. The latter died 3 

 days later. The transplanted piece was then removed and fi.xed in Kopsch 

 fluid. Microscopic examination of this piece showed the superficial portions 

 apparently^ quite normal. The cells were of the average size and their con- 

 tents, although somewhat granular, were not much more so than may be seen 

 frequently in preparations of the normal gland. In the intralobular duct-cells 

 the large, typical secretion granules were often present, sometimes quite filHng 

 up the entire space within the cell. There was very little desquamation in this 

 region. The deeper lobules were much disorganized, although the form of the 

 individual tubules and acini had been fairly well preserved. The elements 

 were pycnotic and there was much desquamation, the lumina containing large 

 quantities of both disintegrated material and necrotic cells and nuclei. 



SUMMARY. 



(1) Pieces of the poison gland, transplanted to the muscles and subcu- 

 taneous regions of the thorax, continued living in their peripheral portions for a 

 period of at least a month, while in one case a few tubules were observed alive 

 after an interval of 2 months. The central portions of the transplanted glands 

 always undergo necrosis. In the course of from three to four weeks the 

 necrotic material is largely absorbed and its place taken by connective tissue. 



(2) There appears to be no marked difference between the pieces trans- 

 planted into the same animal from which the piece of the gland had been 

 excised and those transplanted into other individuals of the same species. 



(3) The transplanted glands show little, if any, power of regeneration. 

 The cells of individual tubules may, however, divide by mitosis and replace the 

 necrotic cells of the same tubules, but any further regeneration apparently does 



