31 
the parasite from the peripheral blood by Atoxyl, and then when the 
blood was free to treat by other drugs, paying no attention to whether 
these drugs had any effect upon the usual phase of the trypanosome 
or not. 
Accordingly a series of experiments was commenced, in which 
rats infected experimentally with Trypanosoma brucei were used on 
account of the rapidity of action of this type of trypanosome. After 
driving out the trypanosome with Atoxyl, the salts of the different 
heavy metals were given ; salts of Silver, Lead, Copper and Antimony 
respectively were employed without any marked results, but when 
Mercury was used in the form of the bichloride a distinct beneficial 
result was at once obtained. While the entire series of controlled rats 
treated with Atoxyl alone succumbed, nearly 70 per cent, of the rats 
given the double treatment survived, never showing any recurrence 
of trypanosomes, and of the remaining 3^^ cent, only 8 per cent, 
showed recurrences of trypanosomes. 
It may be emphasized that the Mercury salt alone has not the 
slightest effect upon the ordinary phase of the trypanosome as seen 
in the peripheral circulation. This appears to demonstrate clearly 
that the two drugs act upon two quite distinct phases. 
Similar results are at present being obtained with other classes 
of animals, and indications of like results w^th the more slowly acting 
Trypanosoma gambiense of sleeping sickness. , 
The two di'ugs are likewise being employed in the treatment of 
sleeping sickness in man, and the results so far obtained are distinctly 
encouraging. 
Plimmer and Thomson, ‘ A Preliminary Summary of the Results 
of the Experimental Treatment of Trypanosomiasis in Rats’ (Proc. 
Roy. Soc, July 20th. 1907), got the best results by combining Atoxyl 
and the different Mercury preparations (Sozoiodol, Donovan’s 
solution), and certainly some of the rats were cured. They also used 
lodipine. Plimmer and Thomson were able to confirm Ehrlich’s 
experiments on atoxyl-resistance. 
Plimmer and Thomson. ' Further Results of the Experimental Antimony 
Treatment of Trypanosomiasis in Rats ’ (Proc. of the Royal Soc., 
read Nov. 7th, 1907), recommend for the treatment of sleeping 
sickness Potassium antimony! tartrate. Trypanosomes disappear 
very rapidly, but there is a bad effect on the rats treated. They 
