456 
E. NOCARD. 
The tetanic toxin I used was prepared at the laboratory of 
Mr. Metchnikoff ; it is in powder; it is kept in vacuum, away 
from light and heat ; it has conserved all its strength for more 
than a year. It kills little mice at the dose of one-thousandth of 
a milligramme ; at this dose it gives lockjaw to large mice, but to 
be sure to kill them one-thousandth of a milligramme is neces¬ 
sary. 500-gramme guinea pigs died tetanic when they received 
one-hnndredth of a milligramme of that toxin. 
In a first series of experiments made upon 16 horses, I cal¬ 
culated what dose minima of that toxin was to be injected to a 
horse to kill him. For horses weighing from 430 to 480 kilo¬ 
grammes, the dose minima always fatal is 6 milligrammes ; 
horses that receive but five milligrammes resist in the propor¬ 
tion of I to 3, and in one experiment of i to 2. In general, it 
is after an injection of six full days that the first symptoms oc¬ 
cur ; in some subjects they may be present after five days ; in a 
few others, only 7 days after the incubation. The duration of 
the disease varies from two to seven days ; horses from Hung¬ 
ary or Galicia are affected sooner and qtiicker ; Normandy and 
Danish horses resist better. 
It became easy to establish the exact curative value of the 
dry serum from Hochst. The only difficulty was its high price. 
I remarked above that the house from Hochst asked 30 marks 
(over seven dollars) for each curative dose of dry serum ; when 
we asked for a number of bottles of serum we were asked the 
double (60 marks) for the dose of 5 grammes of dry serum. Our 
budget did not permit the expenditures. 
I avoided the question in using, in most of my experiments, 
instead of the serum from Hochst, an equivalent dose of the 
serum prepared at the Institute Pasteur ; it then became neces¬ 
sary to establish the relative value of these two serums. Mr. 
Metchnikoff has kindly settled this delicate operation ; in sev¬ 
eral instances, he has experimented comparatively with a dry 
serum delivered by the house of Hochst in December, 1896, and 
one prepared at Pasteur’s in February, 1897, and furnished from 
horse No. 4. In all those experiments, these two serums have 
