791 
horse albumen may remain circulating in the blood for a longer or 
shorter time. 
According to Lemaire,') who investigated low long the horse albu- 
men can be shown in the blood of children that received an injection 
of diphtheria serum, also produced by horses, this albumen remains 
present for at least 10, and at most 50 days. 
That horse albumen remains circulating longer in one individual 
than in another, is referred until now to the fact that the production 
of antibodies individually differs a great deal. The more antibodies 
the organism produces, the sooner the horse albumen will disappear 
out of thé body. 
According to our supposition a second factor is of influence upon 
this, namely the qeantity of horse serum. 
We have experimentally proved the rightness of this supposition 
in the following way: 
Two goats of about the same age and size, got each one subcu- 
taneous injection of antitetanus serum, which we had obtained from 
horses and accurately tested. One goat (A) got 80 A.U. (Brnrine- 
Errvicu) in 20 c.e. serum, the other (B) 80 A.U. in 40 ee. 
serum. Afterwards both goats have been bled four times, namely 
on the 10%, 17%, 24th and 31st day after the inoculation. With the 
serum with which these bleedings supplied us, a great number of experi- 
ments have been taken on white mice, to determine, if the antitoxine 
disappeared sooner out of the blood of goat A than of goat B. 
Every time increasing doses of goat serum were administered 
subcutaneously into series of mice under the skin of the back. Exactly 
after 24 hours these mice and also a control-mouse got a lethal 
dosis of tetanustoxine under the skin of the left hind-leg, which killed 
the control-mouse regularly in 3 days. This constant toxic action 
has been reached by using a tetanustoxine, filtered through a CHaM- 
BERLAND filter, precipitated by means of sulfas ammoniae and dried 
in vacuo; from this toxine every time 50 m.g. was taken for each 
experiment, dissolved in 10 ce. physiological salt solution; from 
this, a hundred times diluted solution, 0.3 ¢.c. has been injected 
into each mouse. 
The sera we got from the first bleeding, proved to act equally 
immunizing. Those from the second bleeding (17 days after the 
inoculation) on the contrary, did not show any more an equal 
immunizing action (see experiment n° 1). 
Also 24 days after the injection the serum of both goats still 
1) These de doctoral. Paris 1907. 
