TRANSMISSION OF INFECTIOUS JAUNDICE 67 



to Tir W of an inch) and are characterized by pointed and 

 usually hooked ends (Fig. 5G). According to the workers in 

 Japan the undulations are irregular and more like those of the 

 relapsing fever spirochsetes than like those of the spirochaete of 

 syphilis. Noguchi, however, states that the number of coils in 

 a given length is greater than that in any spirochaete hitherto 

 known, there being ten or twelve coils in five ju (y^W of an inch). 

 The figure (Fig. 5G) shows only the gross undulations of the 

 organism and not the individual coils. From their descriptions 

 it would seem that the Japanese workers have mistaken these 

 gross undulations for the true coils. Noguchi believes this 

 spirochaete to have characteristics sufficiently distinctive to war- 

 rant its being placed in a new genus, Leptospira. The spiro- 

 chsetes become most numerous from the 13th to the 15th day of 

 illness, and begin to diminish and degenerate by the 24th or 

 25th days, though they may continue to be excreted with the 

 urine for six or seven weeks. 



It is probable that the spirochaetes gain access to the body 

 either by way of the alimentary canal or directly through the 

 skin. The disease can be experimentally transmitted to guinea- 

 pigs by applying an emulsion of diseased liver to the shaved but 

 uninjured skin, infection taking place in as short a time as five 

 minutes. Infection is more certain if any abrasion of the skin 

 exists. 



It has been shown that both the urine and the faeces of infected 

 people contain living spirochaetes and that these excretions are 

 infective. Since infection can occur directly through the skin 

 contact with contaminated ground is dangerous and probably 

 accounts for the prevalence of the disease in certain mines in 

 Japan. Rats have been shown by Japanese investigators to 

 serve as a reservoir for infectious jaundice. The spirochsetes are 

 very common in rats, especially in the kidneys, being con- 

 stantly excreted with the urine. Examination of 86 rats in 

 cities and coal mines in Japan where infective jaundice occurs 

 showed that nearly 40 per cent carried virulent spirochaetes in their 

 kidneys, in most cases demonstrable by microscopic examination 

 of kidney tissue or urine as well as by experimental inoculations. 

 In America the parasites have been demonstrated in wild rats 

 caught in the vicinity of New York City and in Nashville, Tenn. 

 The ease with which rats may contaminate food with their ex- 



