APPENDIX 323 



framboesia (yaws or pian), filariasis and Vincent's angina, 

 salvarsan appears to be equally as specific as in syphilis. 

 It may be emplo3'ed in nervous disorders in which arsenical 

 medication is indicated and exerts either a beneficial or cura- 

 tive effect, according to Best, in acanthosis nigricans, ulcus 

 tropicum or phagedoenicum, variola, verrucae planae, Syden- 

 ham's chorea, scurvy, dermatitis herpetiformis, quartan and 

 tropical malaria. Thus in many diseases the tonic, stimula- 

 tive and alterative action of arsenic is linked with the germi- 

 cidal effect of the drug. Good or indifferent results have 

 been reported in Aleppo boil (Oriental sore), ansemia, kera- 

 tosis follicularis, leprosy, lichen planus, lupus vulgaris, my- 

 cosis fungoides, pellagra, pityriasis rubra, tuberculosis and 

 experimental tick fever. 



In chancroid, bilharziasis, Hodgkin's disease, psoriasis, 

 scarlet-fever, trichinosis, sarcoma, carcinoma and trypano- 

 somiasis, the drug appears to be without appreciable effect. 

 In explanation of the last it is alleged that the trypanosomes 

 are more susceptible of being rendered arsenic-fast than are 

 the spirochaetse. 



In veterinary medicine salvarsan has rendered signal ser- 

 vice and a specific effect, particularly in pleuropneumonia 

 of horses and African glanders (lymphangitis epizootica). 



Acquired Resistance of Spirochcetce to Salvarsan. — It is 

 generally known that trypanosomes possess the power of 

 adapting themselves to circumstances, for instance preser- 

 vation against injurious influences. In other words, they 

 may become immune to their own antibodies or chemicals di- 

 rected against them, as arsenical preparations. This resis- 

 tive property then becomes a characteristic of the organism 

 and may be transmitted from generation to generation. Al- 

 though this characteristic has never been demonstrated to 

 obtain for the spirochaeta pallida, it is presumed from anal- 



