88 THE ORIGIN OF LIFE 



sent entre 50 et 65, et si on les chauffe graduelle- 

 ment, on constate qu'avant de mourir elles perdent 

 graduellement aussi leur activity c ? est-a-dire leur 

 pouvoir de provoquer des fermentations: car celles-ci 

 deviennent tres penibles a. 45 et s'arretent a pen 

 pres comple*tement h 50 . 1 



In regard to the tubes employed, it should be 

 said, they have been sent to me hermetically sealed, 

 and have only been opened for the purpose of 

 charging them with their respective solutions, when 

 they have been immediately re-sealed. The tubes 

 themselves have been thoroughly sterilised during 

 the process of making. Being little more than 

 three inches long, in the process of rounding the 

 lower end, and afterwards drawing out and clos- 

 ing the upper extremity, each tube has been made 

 nearly red-hot throughout its whole length, as I 

 have seen having purposely been present during 

 the making of some of them, in order to satisfy 

 myself in regard to this point. 



1 On the question of the death-point of enzymes, the same 

 writer says (p. 90) : " Toutes les diastases ont comme la 

 sucrase, une temperature optima et une temperature mortelle. 

 Elles ne sont pas les memes pour toutes, mais fl n'y a pas 

 d'enormes differences, et, en general, la temperature de 75-80 

 leur est rapidement funeste ... la sucrase, par exemple, pro- 

 vient de la levure, qui supporte difficilement 60." 



