298 THE CAUSE OF HEALING 



dead tissues, especially that of suprarenal gland, in 

 the strength of 100 per cent, would augment the action 

 of the azur dye, but they would not in themselves 

 induce divisions or even the early stages of mitosis 

 in the experimental ten minutes. We had therefore 

 made arrangements to concentrate these extracts so 

 as to see if they would, if used in greater strength, 

 induce divisions by themselves. At first it was thought 

 better not to boil down the extracts for fear that the 

 boiling might spoil the substance which augmented 

 the action of the dye. The extracts were therefore 

 placed in test-tubes, which were lightly plugged and 

 put aside in the laboratory. As already mentioned, 

 it was necessary to test these extracts from time to 

 time to see whether they might become more effective 

 as concentration occurred. When they were originally 

 made they were sterile, because it may be remembered 

 that they had been kept at 60 C. for twelve hours after 

 filtration. Repeated examination of some of the tubes, 

 however, caused them to become infected, and in 

 consequence putrefaction set in in those tubes. After 

 they had all been kept for three weeks it was noticed 

 that the augmenting action of the contents of one 

 of the infected tubes of suprarenal extract seemed 

 to be increased. One cc., or even a few drops, of 

 this extract, if added to the azur dye and made up 

 in a jelly, caused advanced mitosis in lymphocytes, 

 whereas with the other sterile tubes it seemed to require 

 about the usual quantity of extract to augment the 

 action of the dye. It was particularly noticed that 

 this tube which contained so efficient an extract had 



