S24 APPLIED IMMUNOLOGY 



ogy and clinical experience that spirochaetae pallida may also 

 exhibit drug-fast properties. Thus are explained the failures 

 of mercury to influence syphilis after the first few months in 

 many cases. In like manner, the spirochaetae may become 

 tolerant or resistant to the influence of arsenic when ad- 

 ministered in salvarsan and neosalvarsan. It would appear 

 that early, small or sublethal doses of these drugs may be 

 responsible for the production of arsenic-fast or immune 

 spirochaetae. Consequently, the inference is strong that the 

 treatment of syphilis should be intensive from the start, 

 thereby avoiding relapses, significant of immunity on the 

 part of the spirochaetag. This is best accomplished by repeated 

 full-sized intravenous injections of salvarsan, the number 

 being controlled by the stage of the disease and the Wasser- 

 mann reaction. 



Contra-indications and Precautions. — Salvarsan is con- 

 tra-indicated in advanced degenerative diseases of the central 

 nervous system, in severe non-syphilitic retinal and optic 

 disease, in marked disturbances of the cardiovascular sys- 

 tem, as acute endocarditis, myocarditis, with or without 

 nephritis, extensive degeneration of the blood-vessels, and 

 angina pectoris, in any form of non-luetic nephritis, in dia- 

 betes, in aneurism independent of lues, in pronounced foetid 

 bronchitis and pulmonary tuberculosis, and in persons mani- 

 festing an idiosyncrasy for arsenic. Chronic valvular heart 

 disease, syphilitic endarteritis, aneurism and endocarditis 

 are not contra-indications. In cases of malnutrition, ca- 

 chexia and infantile congenital syphilis great care as to 

 dosage must be exercised. In incipient tabes, early paralysis 

 and epilepsy of syphilitic origin, salvarsan can be employed 

 successfully only when administered early. 



Certain precautions are imperative and must be observed 



