1894 - 95 .] Antivcncnc and Immunization against Venom. 459 
that the serum should be in such a state that it would remain 
unchanged during at least several weeks. It was found that this 
could be insured without any appreciable loss of antidotal power 
by drying the freshly separated serum in the receiver of an air- 
pump, over sulphuric acid, after it had been passed through a 
Chamberland’s filter. A perfectly dry and easily pulverisable solid 
was thus obtained, which may be kept unchanged for probably an 
indefinite time, and from which a normal serum can readily be 
prepared as required, by merely dissolving a definite quantity of 
the dry serum in a definite quantity of water. 
To this serum, whether in the dry form or in solution, it would 
be convenient to apply the name “ antivenene.^^ 
The experiments now to be described were made with anti- 
venene derived from the mixed serum of three rabbits, which had 
last received a dose of cobra venom equivalent to thirty times the 
minimum-lethal. I avoid the expression “immunized against” 
thirty times the minimum-lethal dose, for, as a matter of fact, an 
animal is always protected, or immunized, against a dose consider- 
ably above the last which it had received. 
The experiments were so planned as to obtain, in three or four 
different conditions, as exact a definition as possible of the antidotal 
power of the antivenene. In the meantime, four series of experi- 
ments have been undertaken on rabbits. In one series, the venom 
was mixed outside of the body with the antivenene, and im- 
mediately thereafter the mixture was injected under the skin 
of the animal; in the second series, the venom and antivenene 
were almost simultaneously injected into opposite sides of the 
body ; in the third series, the antivenene was injected some 
considerable time before the venom ; and in the fourth series, the 
venom was first injected, and thirty minutes afterwards the 
antivenene. In the experiments of the third and fourth series, also, 
the venom and antivenene were injected under the skin of opposite 
sides of the body. 
All, or nearly all, the experiments required- to define the exact 
quantity of antivenene that is sufficient to prevent death from 
different lethal doses of venom have as yet been made only in the 
first and fourth of these series. They are, however, in some 
respects the most important of the series : as the conditions for 
