506 Messrs. H. G. Plimmer and J. D. Thomson. [July 20, 



Trypanroth. 



This was discovered and first used by Ehrlich. When used alone it 

 lengthened the course of the disease in both Nagana and Surra to about 

 14 days, but in all cases the spleen was found to be as much enlarged as in 

 the control, and living trypanosomes were invariably found post mortem. 



Arsenious Acid. 

 This was used at first simply dissolved in water, and later, in order to try to 

 avoid the irritation and sloughing invariably produced, in a solution slightly 

 over-neutralised with carbonate of soda. When injected before the fourth 

 day of Nagana and Surra, arsenious acid caused the disappearance of the try- 

 panosomes from the blood, but they invariably recurred before death. It was 

 given in doses of 1 milligramme, and one rat lived as long as 26 days, two to 

 16 days, and one to 17 days, each of these rats having taken 6 milligrammes 

 altogether. A very considerable effect was produced on the vitality of the 

 trypanosomes, as a rat inoculated from the bone-marrow of one of the 16-day 

 rats did not show trypanosomes in the blood until the ninth day after 

 inoculation. Whether neutralised or not, sores were produced at the points 

 of injection. The spleen was found post mortem to be about as large as 

 that of the controls. 



Atoxyl. 



This substance, which was first used by Thomas and Breinl, has been 

 found by Ehrlich and Bertheim to be the sodium salt of para-amido-phenyl- 

 arsenic acid, with the formula 



NH 2 (C 6 H 4 )AsO.ONa.OH,3H 2 0, 



and Moore, Nierenstein, and Todd* have confirmed this view of its com- 

 position, which differs from that originally published, which stated it to be an 

 anilide of metarsenious acid. 



This is the most important substance, so far discovered, in relation to the 

 treatment of trypanosomiasis. In all cases of Nagana and Surra (with the 

 exception of the atoxyl-proof cases mentioned below), atoxyl causes the 

 entire disappearance of the trypanosomes from the blood, so that rats 

 inoculated with the blood when it was microscopically free from parasites 

 failed to take the disease ; but the trypanosomes, in our experience, have 

 invariably recurred, and death was only delayed for a period varying with 

 the dose and with the time of commencement of the treatment. When the dose 

 was sufficient, e.g., 1 to 1*5 c.c. of a 5-per-cent. solution in three to five doses 



* "On the Treatment of Trypanosomiasis by Atoxyl .... followed by a Mercuric 

 Salt," etc., ' Biochemical Journal,' vol. 2, Nos. 5 and 6. 



