BACTERIAL PROTEINS 27 



molecule. This is true gf our cellular substance. 

 I may recall the further fact that the sulphur 

 is so masked that even in the laboratory of so 

 eminent a chemist as Kossel it was not detected 

 in bacterial cellular substance. It is well known 

 that in proteins sulphur exists in two forms, one 

 being readily split off with dilute alkali forming 

 a sulphide, while the other is obtained only 

 when the disruption of the protein molecule is 

 carried much further. The former is wanting 

 and the latter present in our cellular substance. 

 I do not suppose that all nuclear material has 

 the same elemental constituents, indeed, it is 

 not suppo sable that this is true, but the above 

 facts seem worthy of consideration. 



The laborious and valuable researches of 

 Macallum have shown that nonnucleated or- 

 , ganisms, such as cyanophycea, beggiota and 

 , yeastj?ells, contain nuclein, and this is prob- 

 ably true of every cell which is capable of re- 

 production. We are no longer quite willing to 

 accept the dictum of Schultze, Hertwig and 

 others that every cell must contain a morpho- 

 logically recognizable part, known as a nu- 

 cleus. "We may insist upon the presence of nu- 

 clear matter, but not of nuclei. Some morpholo- 

 ogists have seen the necessity of altering our 

 conception of a cell. Bourne has proposed that 



