1918.] The Fifth Indian Science Congress. elxv 
those oecological factors which, by influencing the water supply 
to the leaves or otherwise, are able to cause an undue accumula- 
tion of carbohydrates in the tissues and thus possibly set up 
abnormal enzymatic action ? 
Several of the obscure diseases now under discussion can 
be communicated to healthy plants by budding or grafting, and 
this fact has been considered by some investigators to support 
the theory that such diseases must be due to an organism. 
is fact, however, is in no way incompatible with the theory 
that such communication of the disease is due to the effect 
exercised by the abnormal metabolism and enzymatic activity 
of the “ diseased’ buds or scions on the healthy tissue of the 
protoplasm is sufficiently depressed by a deficient water-supply 
or other factor there is reason to believe that the permeability 
of the protoplasm is altered and that enzymes are then able to 
such as water-supply, may in some cases be communica 
ety plants by means of very small quantities of sap from 
-. . . 
10. As regards the general question of diseases it 18 
Occology and Pl believed that, although the part peer’ 
diseases pactealiy: by x satay fungi and bacteria is as aT le 
actors, the importance of oecological factors like water-supply 
= deficient light and excessive competition. In many other 
‘ses. when these factors have impaired the normal resistance 
