86 Chapter IV 



fact that in the preparation of the extract in physiological salt solution, 

 one part only of the soluble digestive ferment may be set at liberty. 



The solvent action of extracts of macrophagic organs must in fact 

 [92] be attributed to the presence of a soluble ferment in the cells of 

 which these organs are made up. As the diastases are distinguished, 

 in general, by their great sensitiveness to heat, we tried the action of 

 our extracts after a preliminary heating, when it was found that a 

 temperature of 56 C., applied for three quarters of an hour, com- 

 pletely abolished the solvent action of the extracts upon the red blood 

 corpuscles of the goose. The soluble ferment of macrophagic organs, 

 to which we propose to give the name of macrocytase 1 or macrophage 

 ferment, is in many respects analogous to the actino-diastase of 

 Mesiiil, described in the preceding chapter. 



With a view to obtain more complete information on the cytases 

 I suggested to Tarassewitch that he should make a detailed study 

 of them ; this he has carried out in my laboratory. He has demon- 

 strated that the macrophagic organs of other mammals than the 

 guinea-pig, especially those of the rabbit and dog, exert the same 

 solvent action on the red blood corpuscles. He has also established 

 the fact that this action applies not only to the red corpuscles of the 

 goose but extends also to those of several other birds and mammals. 

 Tarassewitch succeeded in confirming the injurious action of heat on 

 macrocytase. Extracts of macrophagic organs which contain much 

 debris in suspension, when heated for an hour at 55'5C. in certain 

 cases lose their solvent property for red blood corpuscles ; sometimes 

 this temperature brings about merely a weakening of the macrocytase. 

 In order to destroy it surely and completely, the suspensions must be 

 heated at 58'5 62 C. for an hour. If, however, instead of heating 

 the entire suspension, we first pass it through filter paper, the clear 

 fluid filtrate is deprived of its diastatic action even after it has been 

 heated at 55'5C. for three quarters of an hour. 



Of all the other organs of which extracts have been kept in pro- 

 longed contact with the red blood corpuscles of birds, the pancreas 

 alone lias shown a very well-marked digestive action. Extracts of the 



1 Some years ago it was proposed to give the name of cytase to the ferments 

 which digest cellulose. Thus Laurent, in the work analysed in the second chapter, 

 applies it to the ferment secreted by the bacilli which attack the vegetable membrane. 

 We think that the cellulose ferment should be designated by the name of cellulosase 

 and that the name of cytase would be more suitable for a soluble ferment which 

 digests the cells. 



