Gr. H. F. Nuttall and E. Hindle 
221 
Fabrikation who manufacture tryposafrol. These gentlemen desired 
that the claims advanced by the discoverers of the dye (Brieger and 
Krause) should be put to an independent trial and it was agreed that 
preliminary tests should be carried out in Cambridge, and, if positive 
results were obtained, that field experiments with animals suffering from 
Nagana should be carried out in Africa under the auspices of the Quick 
Laboratory Expedition then contemplated. The Aktien-Gesellschaft 
subsequently sent us various samples of tryposafrol and novo-tryposafrol 
for experimental purposes, the last samples being posted about 27. VI. 
1914. We asked for the latter samples because we thought that the 
first negative results obtained might be due to some difference in the 
composition of the samples which we had received and tested. 
In a letter from the Aktien-Gesellschaft dated as late as 7. vii. 1915 
we were given further information regarding tryposafrol and about the 
samples we had used with negative results and returned to Berlin for 
chemical examination. The writers assured us that all the samples re¬ 
ceived by us were of the same chemical constitution and similar to those 
used by Brieger and Krause. They gave us the following particulars: 
Tryposafrol readily dissolves in boiling water in the proportion of 
11 : 00; even more concentrated solutions can be prepared in this 
manner. In a 1 % solution hardly any of the dye separates on cooling. 
(We had found that scarcely any of the dye went into solution in cold 
water, a fact which Brieger and Krause do not state in their publications.) 
Novo-tryposafrol differs from tryposafrol through being a tannin 
compound ; it is barely soluble in boiling water and is only administered 
in suspension. Brieger and Krause recommend the following doses: 
for cattle and other large animals 1 g. thrice a day dissolved in much 
water; for pigs (swine fever) and dogs (distemper) 0-1 g. thrice daily. 
Dr Curschmann had tested the dye and found it non-toxic in the dose 
of 0-3 per kilo, of animal in the case of dogs, guinea-pigs and rabbits. 
We shall now turn to our own experiments with tryposafrol and 
novo-tryposafrol on guinea-pigs infected with Nagana and upon dogs 
infected with piroplasmosis. 
Experiments in the treatment of Nagana in Guinea-pigs. 
ls£ series. 
Three guinea-pigs (Nos. 1, 2 and 3) were inoculated subcutaneously 
on 4. vi. 1914 (day 1) with infected guinea-pig blood containing 15 
T. brucei per field. Treatment began on the day of inoculation, 0-05 g. 
of novo-tryposafrol being given daily in bran and water. The faeces were 
