440 SCIENCE PROGRESS 



the proteases that can be prepared from leaves, he found that 

 the ereptasic power was the only one present, coagulable 

 proteids remaining unaltered. 



In the course of some very important researches published in 

 1902, and carried out in the well-known Carlsberg laboratory, 

 Weis came to the conclusion that in the course of the germina- 

 tion of barley two proteases are involved in the proteoclastic 

 processes. Their separate activities could be demonstrated by 

 the action of stannous chloride, or of prussic acid. The first 

 stage led to the formation of proteases, the second to the 

 appearance of crystalline, non-proteid compounds. Weis 

 referred these activities to a peptase and a tryptase respectively. 

 He claims to have been able to distinguish clearly between the 

 parts played by the two enzymes, the peptase being very 

 rapidly brought into action, and very soon stopped ; the tryptase 

 commencing more slowly and continuing long after the cessation 

 of the activity of the peptase. He says that true peptone only 

 appeared in very small quantity. Among the products of the 

 activity of the tryptase he found amino-acids, hexone bases 

 such as lysin, etc., and free ammonia. 



In ungerminated barley Weis detected a very feeble peptasic 

 power, but no tryptasic fermentation occurred. The latter 

 appeared suddenly on the fourth day of germination. 



In the light of the work published since 1902 Weis's results 

 show nothing which is opposed to the view that his " tryptase " 

 is really ereptase, as Vines contends. 



In pursuance of the view already stated, Vines carried out 

 later a series of researches which had for their starting point the 

 different degrees in which, with his mixed extracts from various 

 sources, the fibrin-digesting and the peptolytic powers they 

 possessed were affected by modifications in the conditions 

 under which the digestions were carried on. As these led to 

 important conclusions it is well that they should be stated in 

 some detail. 



Attention may first be called to the work of Mendel and 

 Underhill on the action of papain. Using a 1 per cent, solution 

 of sodium fluoride as an antiseptic they found this salt affected 

 prejudicially the digestive activity of the enzyme in so far as to 

 retard or altogether inhibit the decomposition of peptone, while 

 its formation from fibrin was not materially checked. Vines, 

 from using other antiseptics and obtaining contrary results, was 



