Abstract
There are subjects in whom thiaminase can not be found in their faeces by the ordinary way, while its presence can be verified by the following procedures : To 1.0 ml of the faeces extract(1 : 10) was added pyridine in a final concentration of 10^<-3>M, and decomposition of thiamine was performed. Such subjects seem to form about 21% of the ordinary people. Also there are subjects in whom thiaminase in their faeces can be demonstrated by the procedure above mentioned after oral administration of sulphur powder. The bacteria responsible for producing these thiaminase could not be found.
