482 Dr. L. Rogers. On the Physiological [Mar. 31, 



my specimens, which are caught by the fishermen in their nets during 

 the calm cold-weather months with a frequency which is in propor- 

 tion to the number of fish taken. By small payments they were 

 induced to bring them to a tank which I had constructed near the 

 beach, in which they usually only lived a few days, although some 

 survived several weeks. By making them bite on a watch-glass 

 covered with a thin layer of guttapercha tissue stretched tightly across 

 it, they eject the poison into the glass as clear drops free from all 

 saliva. This is then dried over calcium chloride or strong sulphuric 

 acid, and can then be kept indefinitely in dry well-corked glass tubes, 

 without losing its potency. The snake which is met with in greatest 

 abundance in Puri is the Enhydrina Bengalensis, measuring from three 

 to five feet in length, and it has a thick body and a large head. This 

 species also furnishes the largest amount of poison, and from this alone 

 have I yet been able to obtain a sufficient quantity to allow of a con- 

 siderable number of experiments being performed with it. That of 

 four other species, belonging to three different genera, has also been 

 obtained in small quantities, so that four out of the six genera of 

 Indian Hyclrophidae have now been examined, and will be dealt with. 



Appearance and Quantity Ejected. 



When the clear watery drop of poison is dried, it forms white 

 shining scales, freely soluble in water or normal salt solutions, and 

 differing from the poisons of Cobra and Daboia by the absence of the 

 yellow tinge of the latter. The only exception I have met with was a 

 faint yellow tinge in the dried poison of a Disteira cyanocincta, the 

 others having all been colourless. 



The quantity of poison ejected at a single bite is of great import- 

 ance in relationship to the deadliness of these snakes, and fortunately 

 it is very small. In many of the smaller species it is often impossible 

 to get a drop at all, but probably when free in the water they can eject 

 more poison than when being held close behind the head, with conse- 

 quent great limitations of their power of motion. The amount of 

 dried poison obtained from a single bite of thirteen different fresh 

 specimens of the Enhydrina was weighed, and the average quantity 

 was found to be 0*0094 gramme, or almost one centigramme. This is 

 very much less than that obtainable from a Cobra or a Daboia, for the 

 average amount of poison (dried) obtained from a Cobra is, according 

 to D. D. Cunningham, 0'254 gramme, or twenty-five times as much as 

 is obtained from an Enhydrina. In fact, so small is the amount, that 

 at the end of a season I had only been able to obtain about one-third 

 of a gramme of the latter poison, and for most of which I am greatly 

 indebted to Dr. Reid of Puri. The poison also appears to be slowly 

 formed, as a week after a snake had been made to bite, it is usually 



