622 THE ANIMAL PARASITES OF MAN 



cord. These changes cause compression of the blood-vessels, and 

 so lessen the supply of blood to the brain and spinal cord. Further 

 changes in the latter organs result in the production of the symptoms 

 that have given the disease the name of " sleeping sickness." 



The disease due to Trypanosoma rhodesiense generally runs a more 

 rapid course than that due to T. gambiense. The torpor and sleepi- 

 ness may not be obvious or be very slight, and the enlargement of 

 the lymphatic glands of the neck also may not be marked or may 

 appear to be absent. The duration of . the disease often appears 

 to be from three to six months. 



Treatment is only of use if commenced in the earlier stages of 

 the disease. The substances of most value so far are arsenic in 

 the form of atoxyl (introduced by Wolferstan Thomas in 1905) and 

 antimony in the form of tartar emetic. Castellani and Chalmers and 

 Manson recommend treatment by combining the use of both substances. 

 The combined treatment is recommended not only because both sub- 

 stances have been proved of service independently, but also because 

 certain strains of trypanosomes resistant to arsenic are known, and 

 trypanosomes can develop a resistance to arsenic. Such forms, that 

 would not be affected by the atoxyl, are left open to attack by the 

 antimony salt. Daniels also recommends combined arsenic and 

 antimony treatment, and (1915) uses atoxyl and antilnetin. 



Atoxyl is best given intramuscularly in 10 per cent, solution in sterile 

 normal saline solution. Galyl is also said to have given good results. 



Castellani and Chalmers recommend : (i) Hanson's method of 

 administration of atoxyl, viz., 2 to 3 gr. of atoxyl are given by 

 intramuscular injection every third day for at least two years ; or 

 (2) Broden and Rodhain's method, 7^ gr. of atoxyl by intramuscular 

 injection every fifth day. For the combined therapy by atoxyl and 

 antimony they recommend the following : " An atoxyl injection 

 (3 g r -) is given every third day or 7^ gr. every fifth day, and sodio- 

 tartrate of antimony (Plimmer's salt) is administered daily, 2 gr. 

 dissolved in a large quantity, of water (2 pints) by the mouth or 

 by the rectum. Tartar emetic, however, is best given by intravenous 

 injections, using solutions of i in 100 or i in 1,000. The dose of 

 the drug to be given is 5 to 10 eg. per injection. It is important 

 that none of the fluid of the injection should escape into the 

 surrounding tissues, as a violent inflammation may result. These 

 injections should be administered monthly on ten consecutive days 

 for a long period." 



Macfie and Gallagher (1914) injected 6 gr. of atoxyl intra- 

 muscularly every week in cases infected with. 7 . nigeriense in the Eket 

 district of Southern Nigeria. 



Large doses of atoxyl were often said to cause distressing results 



