146 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 
The venoms of Enhydrina and Distira, two marine snakes, contain very 
little of the haemolytic principles, but are many times more toxic than that of 
the most dreaded land snake, the cobra. One minimal lethal dose of the 
venom of Enhydrina can destroy about 3} part of the blood of the animal 
injected with this venom. (Rogers.) 
The resistance of the hemolysins is shown to be much weaker than that of 
the neurotoxins against peptic digestion (Flexner and Noguchi). 
So much for the biological isolation of the neurotoxins from the hemolysins. 
The next phase of this subject is of its chemical isolation, which was first 
accomplished by Kyes and later confirmed by von Dungern and Coca. Kyes 
succeeded in isolating venom lecithid by shaking an aqueous solution of 
venom with a chloroform solution of lecithin. ‘The venom lecithid is exclu- 
sively hemolytic, but not at all toxic. On examining the venom solution 
from which the venom lecithid has been separated by centrifugalization, Kyes 
found that the original toxicity of cobra venom was left in the aqueous portion 
in undiminished quantity... Thus the hemolytic and neurotoxic principles 
have been completely separated. The injection of the venom lecithid in a 
large quantity does not kill the animal. On the other hand, the remaining 
venom solution is no longer hemolytic, but still highly neurotoxic. Von Dun- 
gern and Coca prepared the lecithid by the same method, but they once 
found that the venom solution still contained a certain amount of hemolysins, 
while another time the removal of hemolysins was complete. 
Morgenroth prepared venom lecithid by a slightly modified method, in 
which methyl alcohol was substituted for chloroform. This preparation 
was not only hemolytic, but also neurotoxic to a certain extent. This 
apparent difference from the result ascertained by Kyes was later explained 
by him to be due to the adherence of the neurotoxic principles to the precipi- 
tated lecithid. Kyes assumed that weak alcohol contains enough water to hold 
the neurotoxins in solution, and at the moment of the precipitation of the 
lecithid with ether the neurotoxins are mechanically carried down. 
Faust finally isolated an active substance, the ophiotoxin, from cobra venom 
by pure chemical processes.’ 
Ophiotoxin is obtained from the non-coagulable, non-dialyzable portion 
of cobra venom by means of 10 per cent metaphosphoric acid, which precipi- 
tates all the biuret-giving substances. Now, the filtrate contains only protein- 
free active substance of the venom, and by adding alcohol it is precipitated 
out. It is an amorphous, somewhat yellowish powder, soluble in water, and 
forms foam by shaking the solution. It is slightly acid, non-dialyzable, and 
nitrogen-free; it has the formula of C,,H,,0,). According to Faust this sub- 
stance belongs to the same group as sapotoxins. Its action is nearly 5 times 
stronger than the native venom, but with a great tendency to become inactive 

1 Jacoby made a comparative study of the effects of the isolated neurotoxin and the raw venom of cobra, 
and found that there is no essential difference in their pharmacological actions on the nervous 
system. Salkowski-Festschrift, 1904, Berlin. 
2 For the details see ‘‘ Physical and chemical properties of venom,” page go. 
