250 
The results obtained, however, were not what were expected; 
dogs, rabbits and donkeys were used for the experiments, bnt 
invanably after the first injection, even after exposure of the mixture 
for forty-five minutes to a temperature of 3;“ C, the animals became 
infected after a normal incubation period. This fact seemed to 
suggest tiiat the action of Aloxyl was not simply disinfectant, but was 
the result of a co-operation between the living tissues and the drug. 
L hlenhuth, fliibner and WGithe"* in their experimental study of 
the action of Atoxyl on T. cquiperdum came to a similar conclusion 
They state (p. 2g0) : — 
' Unsere Meinuiig geht jedenfalls daliin, dass der Chemismusder 
Atoxylwirkung kein so einfacher ist, wie ihn die Theorie der 
Arsenspaltung supponiert, das vielmehr beim Zustandekomraen des 
wunderbaren therapeutischen liffektes die Kbrperzelle eine ganr 
hervorragende Rolle spielt.’ 
This observation of ours, confirmed by Uhlenhuth, Hiibner and 
Woithe, was the starting point for the following study of the 
therapeutical action of Atoxyl. 
The experiments were divided into two groups, the action of 
Atoxyl and similar compounds on serum proteids being studied 
in vitro and in vivo, respectively. Only the results of the first series 
are here recorded. 
Technique. — 20c.c. af normal serum and 20c.c. of a 2 per cent 
solution of the compound were shaken up for twenty-four hours, and 
the proteids afterwards were precipitated with 35 c.c. of a 2 per cent 
solution of tannic acid. 1 he precipitate was then carefully washed 
for about forty-eight hours and arsenic estimations of the filtrate were 
made from time to time until no trace of arsenic could be found in the 
iltrate. The precipitate was treated with 10-15 c.c. concentrated 
sulphuric acid, and digested in a Kjeldahl flask in the usual way. 
The arsenic estimations were made by SangerV method. Instead 
lydrochloric acid, gold chloride was used as a developer, and proved 
much more sensitive. 
In those cases in which arsenic was found in the precipitate after 
on, some of the original product was dialysed against w^ater in 
parciment sausage-skin, and the dialysate was evaporated to 
clryness and tested for arsenic. 
