152 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 



The experiments here given confirm previous observations respecting the 

 nerve cells of the mussels and giant sea-clam. The nerve cells of these ani- 

 mals are smaller than those of the periwinkle, and are pigmented; but they 

 are somewhat less satisfactory for study than those of the latter animal. On 

 the other hand, they are somewhat less resistant than the cells of the peri- 

 winkle, as is shown by their more rapid disintegration in the controls and 

 correspondingly more rapid neurolysis in venom. 



B. Histological Changes of the Nervous System Produced by 



Snake Venom. 



Our knowledge of histological changes produced by various snake venoms 

 upon the peripheral and central nervous system was quite defective until 

 about 1900. Many valuable contributions have since been added and to-day 

 we are in a position to corroborate physiological findings by demonstrating 

 gross and minute histological lesions which are accountable for the functional 

 disturbances of the nervous system under the effects of various venoms. 



Ewing ' found the changes occasioned in the ganglion cells of a rabbit by 

 moccasin venom to be somewhat specific and of extreme grade. Nissl stain 

 showed a general disintegration of the chromatic substance. The outlines 

 of the Nissl bodies were completely obscured; the substance had been de- 

 posited in a finely granular form all over the cell body and even in the peri- 

 cellular lymph space. In the majority of the large stichochromes neither 

 formed bodies nor reticulum could be distinguished. It was evident that the 

 lesions went much deeper than the chromatic substance, affecting the under- 

 lying cyto-reticulum, which was granular, disintegrated, and in places com- 

 pletely destroyed. The nuclei were very opaque and the nucleoli often 

 swollen and subdivided. The dendrites were often irregular, shrunken, or 

 detached. These changes constitute a true acute degeneration of the cell, in 

 contradistinction to the simple disturbances of chromatic substance, which 

 may be entirely physiological. 



Bailey published his result in the same place. According to him most of 

 the cells of the anterior horn of the spinal gray matter were normal, but a 

 small number presented those modifications in their chromatic elements 

 which probably evidence the early stages of acute degeneration, i. e., ? an in- 

 crease in the granularity of the chromophilic bodies and a fraying out at their 

 edges, with some distinct loss in chromatic substance. The cyto-reticulum 

 is normal. The nucleus may be normal, or there may be an intensification 

 of the surrounding membrane and a thickening of the strands of the nucleo- 

 reticulum. 



A few cells are found in which there is much greater loss of chromatin, 

 the cell bodies appearing extremely pale and no distinct chromophilic bodies 

 being present. 



1 In Gustav Langmann's article "Poisonous snakes and snake poisons." The Medical Record, 1900, 

 Sept 15. 



