INFECTIONS OF THE DIGESTIVE TRACT 227 



It appears to me, therefore, not clear that the methyl 

 mercaptan found by Nencki was not formed during 

 putrefaction outside the body. My scepticism on this 

 point rests partly on the fact that although I have 

 made many examinations of the fresh faeces from per- 

 sons with excessive intestinal putrefaction, I have never 

 been able to find methyl mercaptan by means of the 

 isatin-sulphuric-acid reaction. It appears improbable 

 that methyl mercaptan is produced in the human large 

 intestine in the course of ordinary putrefactive troubles, 

 although it must be admitted that it may perhaps arise 

 under some exceptional conditions. It may be stated 

 before leaving the subject of mercaptan that experi- 

 ments were made upon dogs and monkeys in which ethyl 

 mercaptan in a solution of one part in one thousand 

 parts of water failed, when injected into the large 

 intestine, to give rise to definite evidence of intoxica- 

 tion unless very large quantities were employed. Thus 

 during a period of ten days a dog of medium size re- 

 ceived 20, 30, 50, 56, 110, 110, 110, and 110 c.c. of such a 

 solution on successive days without exhibiting symp- 

 toms. The injection of 50 c.c. of a solution two and one- 

 half parts per one thousand parts was not well retained. 

 It was only when a dose of 120 c.c. of this concentration 

 was introduced into the stomach that vomiting occurred. 

 The rectal injection of an ethyl mercaptan solution of 

 1 : 1000 strength in quantities of 10 to 30 c.c. daily in a 

 medium-sized monkey failed to give rise to symptoms. 



Hydrogen Sulphide. There is reason for thinking that 

 the production of hydrogen sulphide in the digestive 



