140 THE VENOM OF HELODERMA. 



extended toward the periphery. Some of the cells showed a slight swelling. 

 This latter feature was present in both acute and chronic cases, but seemed a 

 more constant feature in the various sections of the chronic cases. This swel- 

 ling of the cell does not seem to be a characteristic feature in the pathological 

 findings of others. No mention of it is made by Lamb, Hunter, or Kilvington. 



The disintegration of the Nissl bodies was the most constant finding in the 

 acute cases, but it is not characteristic, being also found in the chronic cases. 



In none of our acute cases was an eating-out of the cell seen or the complete 

 dissolution of its cytoplasm, etc., as described by Lamb and Hunter. The 

 process after injection of heloderma venom seemed much milder when com- 

 pared with the effect of some of the snake venoms. In the ganglia-cells of 

 our animals the nuclei were for the most part centrally placed and could always 

 be recognized. They were misplaced only in exceptional cases. 



Chromatolysis was a constant feature in the animals living from 48 hours 

 to several days (guinea-pigs AI, A 4 ; rabbits B 1 and B 2 ). In none of the cells 

 was the outline lost; the nuclei were always visible and showed no change in 

 form. These changes corresponded to those of Kilvington, Bailey, Lamb, and 

 Hunter, save that in our cases the cells were in some instances swollen. 



Another change which we found and which was not described by the above 

 authors was the presence of minute areas of hemorrhage in two of our cases 

 (rabbit a 3 and guinea-pig A 1 ) . These hemorrhages were small and scattered 

 through the entire structure of the medulla (rabbit a 3 ), while in guinea-pig A 1 

 they were noted around the central canal of the cord. These hemorrhages 

 have not been sufficiently constant in our series to conclude that they are 

 characteristic for the venom of heloderma. In guinea-pig A 1 the animal had 

 convulsions prior to its death, and the convulsions may possibly be responsible 

 for the hemorrhages. 



We observed a round cell infiltration in two of the chronic cases (rabbits 

 B 2 and A 8 ) ; in the former case (B 2 ) the cell infiltration was found around the 

 posterior septum of the cord, and in the latter animal (a 8 ) around the blood- 

 vessels. In the cases described by Lamb and Hunter, the cells were clustered 

 around the disappearing ganglion- cells, the process being not unlike a neuro- 

 phagia similar to that described by McKinas in poliomyelitis; while the infil- 

 tration in my cases was purely a chronic inflammatory process. As in the 

 animals poisoned by snake venoms, we also found, after injection of heloderma 

 venom, affections of the various cranial nuclei. In contradistinction to Lamb 

 and Hunter's observations, we could not observe any special selective action 

 of the venom on the third and fifth nuclei; in our entire series no preference 

 -could be detected for any one of the nuclei of the cranial nerves. 



The changes in the ependymal cells were similar to those seen by previous 

 authors in the case of snake venoms. A vacuolation of the cells was noted and 

 the canal contained an excess of granular substance. In those cases in which 

 hemorrhage occurred in the white substance (guinea-pig A 1 and rabbit a 3 ) a 

 similar collection of red blood-corpuscles was observed in the canal. 



The results obtained with the Marchi method were negative; no changes 

 were found in the spinal cord of the animal living for 13 days. No changes in 

 the myelin or in the axis cylinder were to be noted. 



