EXPERIMENTAL VENOM POISONING IN ANIMALS 115 



ity of blood mostly disappeared, and it remained fluid permanently or for some 

 time. The kidneys were often haemorrhagic and swollen; the bladder some- 

 times contained bloody urine, and the urine was shghtly albuminous. The 

 irritabihty of sciatic and phrenic nerves was still present after 13 and 28 

 minutes respectively. The brain was found mostly congested. 



ANCISTRODON. 



The actions of the venoms of American species, Ancistrodon piscivorus 

 and A. contortrix, are the same, and are essentially similar to those of the 

 Crotalus on one hand and the Lachesis — including the famous South Ameri- 

 can Bothrops lanceolatus and Trimeresurus of Japan — on the other hand. 

 As has already been pointed out by Mitchell and Reichert, the venom of the 

 water- moccasin contains more neurotoxic constituent than rattlesnake venom, 

 and consequently the degree of local lesions is comparatively less, but para- 

 lytic effects on the respiratory center and motor nerves are stronger. Flexner 

 and Noguchi confirmed these observations. 



LACHESIS. 



The actions of the venom of the snakes belonging to this genus are much 

 the same as those of Ancistrodon and still closer to those of the crotalus 

 venoms. In these venoms, as has been already described, the locally destruc- 

 tive principles predominate, in contrast to the venoms of typical colubrine 

 snakes. 



Careful study of the action of the venom of Lachesis or Trimeresurus 

 riukiuanus on different animals has been made by Ishizaka,^ from which 

 we derive the following: 



The mice and rabbits are fairly susceptible to this venom, the former being 

 killed in one hour if 0.003 g'^'^- ^o 0.005 g"^- ^e given subcutaneously, while the 

 latter require 0.02 gm. to 0.03 gm. per kilo body-weight to be fatal in 4 to 6 hours. 

 The visible symptoms in mice are the local swelling, general depression, and 

 dyspnoea. The respiration becomes gradually slower, irregular, shallower, 

 and finally there is a complete standstill, without convulsions in agony. The 

 heart continues to beat for some time after respiratory cessation. The local 

 symptoms appear from 10 to 15 minutes after injection, and the skin presents 

 violet-dark discoloration and haemorrhagic oedema. The amount of the venom 

 used is a subminimal lethal dose; the inflammatory haemorrhagic tissues 

 become necrotic, and after some time the slough is cast off. In rabbits the 

 symptoms are about the same — local swelling, haemorrhages, dyspnoea, depres- 

 sion, paresis, and slight convulsions before the respiratory cessation. The 

 heart beats some minutes after respiration is stopped. The irritabihty of 

 the phrenic nerve and other muscular nerves is found to be present. The 

 haemorrhages are constant symptoms and are always more pronounced in the 

 lower parts of the body, this perhaps being due to the gravity of the venom. 



> Ishizaka. Studien iiber Habuschlangengift. Zeit. f. experimenteUe Path. u. Therapie, 1907, IV, 88. 



