454 PROTEIN POISONS 



extracted from the cell with dilute alkali, while others are 

 best obtained by dilute acid. In either case the reagent 

 must not be strong enough to destroy the ferment itself. 

 They are non-filterable, or pass through filters slowly and 

 imperfectly. We suspect that their molecular structure 

 is relatively complex, or that they are more colloidal than 

 the extracellular ferments. Under natural conditions the 

 intracellular ferments act only on those bodies which are 

 taken into the cell. The inclusion of bacteria by phago- 

 cytes is essential to the digestion of the former by the 

 intracellular ferment of the latter. This is a phenomenon 

 which may be seen, but cell permeation by foreign bodies 

 is certainly necessary before such bodies can be acted upon 

 by the intracellular ferments, and occurs with soluble 

 proteins as well as with particulate ones. The intracellular 

 ferment bears a wider variation in temperature, and is not 

 so easily and delicately influenced by variations in the 

 composition of the medium in which the cell exists. So 

 far as we know the intracellular ferments do not diffuse 

 from living cells. They are, however, recognizable in the 

 fluids of abscess cavities as the leukocytes disintegrate. 

 We are of the opinion that they are essential constituents 

 of the chemical structure of cells. The reason for this 

 belief will be developed later. The extracellular ferments 

 may be regarded as secretions of cells. Much has been 

 written about cellular and humoral theories. In our opinion 

 every living thing has a chemical structure, which we may 

 designate as a cell if we wish, understanding that a cell is 

 not necessarily something that can be seen, and that it 

 may possess widely different degrees of lability, but we are 

 quite certain that there is no ferment which is not the 

 product of life processes. We have been somewhat sur- 

 prised to find it stated that our own theory of protein 

 sensitization or anaphylaxis is a humoralistic doctrine. 



All ferments are products of life processes, and all life 

 processes are more or less responsive to outside influences, 

 to change in environment. In our opinion the most valuable 

 fact that we have learned in the study of protein sensi- 



