PHYSICAL AND CHEMICAL PROPERTIES OF SNAKE VENOM 83 
globulin-magnesium precipitate allowed a small trace of albuminous body 
to diffuse outside the dialyzer, and the latter gave the precipitate with acetic 
acid and ferrocyanide of potassium, indicating that this was an acid albumin. 
Judging from this he thought the dialyzable protein of venom could not be 
a peptone, but an acid albumin. 
Serum albumin: A very small quantity precipitable with Na,SO, from 
the magnesium filtrate of venom was obtained, but precipitation required 
many hours shaking. It coagulated in redissolved condition at between 
70° and 80° C. 
Syntonin: Some fraction was obtained from the filtrate of an aqueous 
solution of venom previously heated to 98° C. for 10 to 15 minutes by means 
of saturated MgSO,, and still more completely by boiling the filtrate with 
solid MgSO, in saturation. Usually this frees the venom solution of any 
protein matter, but there may be some exceptions, which Wolfenden, in that 
case, thought due to the presence of peptone. He found that the filtrate of the 
boiled venom solution (in water) is acid and forms coagula by neutralization. 
Peptone: Wolfenden employed the method devised by Hofmeister for 
testing peptone: (1) Cobra venom which had been precipitated by satura- 
tion with MgSO, was treated according to that method.* On addition 
of the acid phosphotungstate of soda there was produced a slight opalescence. 
(2) An alcoholic extract of cobra venom was treated with the above method 
and gave similar opalescence with phosphotungstate of soda. The extract 
gave undoubted protein reaction. (3) The dialysates (mixed) of cobra 
venom, after 3 days’ dialysis, gave no acid-albumin reaction, but yielded 
precipitation with Hofmeister’s method. Biuret was negative. (4) A portion 
of cobra venom which was once treated with MgSO, and Na,SO, gave a 
slight turbidity with the acid phosphotungstate of soda. From these experi- 
ments Wolfenden concludes that there are three proteins present constantly 
in cobra venom, namely, globulin, serum albumin, and syntonin and prob- 
ably, in traces only, a fourth, peptone. 
Similar experimental studies have been extended by Wolfenden to the 
venom of Daboia russellii. In this series for the separation of globulin he 
employed precipitation by MgSO,, NaCl, and (NHy).SO,, CO,, and dialysis. 
He found the globulin to coagulate at 75° C. The presence of serum albumin 
was made apparent by precipitation of the magnesium filtrate by Na,SO, and 
the occurrence in the solution of the soda precipitate of an opalescence on 
boiling, within the range of coagulation temperature of serum albumin — 
BOF t0:.807.G. 


1 Hofmeister’s method is as follows: Treat a solution of albumin with saturated solution of sodic acetate 
and then add ferric chloride, until of a blood-red color. At this point the addition of the iron 
is stopped. Neutralize it with sodium hydrate up to a slight acid reaction. Then boil the 
fluid for a few minutes, and filter. The colorless filtrate must not give precipitate with ace tic 
acid and ferrocyanide. Make the filtrate acid with acetic acid and test with an acid solution of 
phosphotungstate of soda (acidified with acetic acid). The ratio of the filtrate and the 
reagent is 4:1. If any peptone is present there is a flaky precipitate, or a turbidity, on 
standing for a few minutes. All the albumins except peptone are removed by the ferric 
acetate. This method is about 50 times more accurate than that of biuret, which can detect only 
in I= 2000. 
