142 THE VENOM OF HELODERMA. 



Pons : Similar changes were noted in the ganglion-cells of this region. 



Mid-brain and basal ganglion: The cells in this region showed a similar 

 picture, though not as many were affected. 



Sections studied from various areas of the cerebral cortex showed little 

 change. 



Guinea-pig Af. — 24 mg. of venom in capsule. Dead in 48 hours. Sec- 

 tions of the medulla only studied. Quite a few of the ganglion-cells showed 

 loss of staining power, indicative of a chromatolysis. The nuclei of the fifth, 

 seventh, ninth, and tenth were affected alike. 



Rabbit Bi. — 2 capsules each 30 mg. placed in the peritoneal cavity. Sec- 

 tions fixed and stained as before. 



Medulla: Chromatolysis of the Nissl bodies and displacement of the nuclei 

 were seen in some of the ganglion-cells of the cranial nuclei. As these sections 

 were cut longitudinally, the orientation of the various cranial nuclei could 

 not be made out with certainty. 



Cerebral cortex : Many of the Betz cells show breaking of the Nissl bodies, 

 displacement of the nuclei, and shrinkage of the cell-body. 



Rabbit B-: — 2 capsules, 30 mg. each, in the peritoneal cavity. Killed at 

 the end of 13 days. Sections fixed in formalin and in Muller's fluid. 



Spinal-cord sections stained with picric acid showed no changes. 



Medulla: Sections stained by the Nissl method show the ganglion-cells of 

 the tenth, ninth, seventh, and fifth cranial nuclei affected. Not all the cells 

 were involved. There was loss of staining power in these cells, although their 

 outlines were well defined. Shadow cells were seen with nuclei faintly present. 

 A slight proliferation of connective tissue was noted in one area around the 

 posterior septum in the medulla. 



Rabbit a^: — 4 capsules (1 capsule 50 mg., 3 capsules 0.3 c.c.) given during 

 a period of 28 days. Tissues placed in formalin 3 hours after death. In the 

 medulla the cranial-nerve ganglion-cells showed some loss of staining power of 

 the Nissl bodies. The fifth in this case seemed less involved than the tenth, 

 ninth, and seventh. A few cells showed vacuolation and displacement of the 

 nuclei. The vessels in the medulla were distended and congested. Slight 

 round-cell accumulation was seen in the perivascular areas. 



