482 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



In cobra poison, on the other hand, we have a venom 

 which would appear to exert little effect on the blood. 

 Marked diminution of cardiac activity is characteristic of 

 all kinds of snake poisoning, except in the case of cobra 

 bite, in which case the circulatory mechanism is not 

 markedly affected unless the dose be very large. 



The principal action of cobra venom on the nervous 

 system consists in an extinction of function, extending 

 from below upwards, of the various nerve centres consti- 

 tuting the cerebro-spinal system, and though no doubt 

 other parts of the nervous system suffer, cobra poison has 

 a special affinity for the respiratory centre. 



Having shown that these two poisons, cobra and daboia, 

 are quite distinct in their primary action, and that the 

 only physiological action of daboia venom is its action on 

 the blood, especially on the blood coagulability, it may be 

 now asked, whether this viper venom contains any of the 

 elements to which cobra poison owes its toxic power. 

 From the result of observations in India, it seems conclu- 

 sive that daboia venom is free from, or contains only the 

 merest trace of, the principal toxic constituent of cobra 

 venom. 



It is now well known, after the work of Calmette and 

 Fraser, that the serum of an animal immunised against 

 cobra poison will protect not only against this posion, but 

 against the poison of other snakes. This, however, is only 

 true to a limited extent. There is one poison, viz., 

 that of Russell's viper, w'hich had been shown by 

 Cunningham and Wall to have a different physiological 

 action from that of cobra venom ; and Kanthack pointed 

 out that therefore one could hardly expect animals 

 immunised against cobra poison to become resistant, and 

 furnish a serum against viper poison. 



Captain Lamb and the writer last year, in a communica- 



