GUMMOSIS 65 



meate the secondary and tertiary membranes without attacking 

 them. No better proof of the specific action of enzymes can be 

 advanced than that given by Jones 10 in his work with soft-rot 

 organisms. An interesting comparison is afforded us by Pro- 

 tomyces macrosporus 11 in which the middle layer of the wall is 

 gelatinized and the endosporium remains intact to become the 

 wall of the extruded sporangium. 



Attention may also be called to the observation that cells 

 under certain conditions, which were observed to be floating free 

 in the gum, vanished upon the addition of water, while under other 

 conditions free cells no longer vanished upon the addition of water. 

 How this proves that protoplasm plays no role in gummosis and 

 that the cell wall is ab initio the seat of the malady is not clear. 

 If we assume that the walls of the cells affected by gummosis 

 have been rendered almost soluble by enzymotic activity, and 

 there has been established an osmotic equilibrium between the 

 colloids within the cells and the gum mass without, contact with 

 water might easily cause the cells to imbibe enough to suddenly 

 burst them and rather quickly complete the hydrolization of the 

 cell-wall. This condition seems to be analogous to the phenomena 

 which are exhibited by tannin masses taken from softened per- 

 simmons. 12 Such tannin masses, when the semi-fluid substance 

 of the disintegrated cell-walls is diluted or replaced by water, 

 will quickly absorb enough of it to cause the cells to burst. 



In studying the cells which did not vanish, Butler finds that by 

 staining with Bohmer's haematoxylin, the gum is stained and the 

 protoplasm is not affected, but by staining with aniline blue 2V. 

 the protoplasm is colored and the gum is not affected. By this 

 differential means he could determine exactly when he was deal- 

 ing with gum and when with protoplasm and arrives at the con- 

 clusion that "the cell contents are free from gum and take no part 



10 Jones, L. R. T Pectinase, the cytolytic enzyme produced by Baccillus caroto- 

 vorus and certain other soft rot organisms. N. Y. (Geneva) Agr. Expt. Sta., Tech- 

 nical Bull., 11: 291-368, 1909. 



11 Vide DeBary A., Comparative morphology and biology of the fungi, myce- 

 tozoa and bacteria, p. 171 . 



12 Lloyd, F. E., The tannin-colloid complexes in the fruit of the persimmon, 

 Diospyros. Biochemical Bulletin, 1: 7-41, pi. 1-3, 1911. 



THE PLANT WORLD, VOL. 15, NO. 3, MARCH, 1912 



