288 B. M. DUGGAE. 



of the fact that it never reaches the stage when it is evident to 

 those not cognizant of the early symptoms. There exists no ex- 

 perimental proof that the disease may be conveyed by infected 

 soil, by contact with diseased trees, by the action of insects or 

 by pollination. 



It is conceivable that all of the diseases mentioned might be 

 induced by chemical substances provided we assume that any 

 chemical body may have the power of stamping upon the proto- 

 plasm the capacity of regenerating itself. This is perhaps the 

 one strong criticism against the enzyme or chemical theory of 

 cause. Nevertheless when we consider how little is known re- 

 garding the cell activities resulting in the production of enzymes, 

 how elemental is our knowledge regarding their production as 

 influenced by the substrate, how complex and difficult are the 

 anaphylactic relations in animals and lastly how mysterious the 

 influence of iron in the cell is upon the production of chlorophyll, 

 we can see at least the possibilities of new lines of research in the 

 case of these so-called physiological diseases. I do not mean 

 at all to imply that there are not ultra-microscopic organisms. 

 Ultra-microscopic organisms, however, must exhibit metabolic 

 functions other than those of propagation, and when they may 

 be obtained in relatively high concentration in body fluids and 

 in plant juices we should have some proof of their metabolic 

 activities, of their respiration. 



I feel that research in these directions has been curtailed by 

 the assumption that any such " organisms" exist, when the proof 

 of it should be possible, and should be furnished by those who 

 maintain their existence. If such organisms exist, it is clear that 

 they are not of widespread distribution, and perhaps do not occur 

 at all as saprophytic organisms, otherwise we should have en- 

 countered them in the various fermentative processes charac- 

 teristic of plant and animal products. We are making an effort 

 to study the metabolism of such assumed organisms. Many 

 difficulties beset the investigator and there is no problem known 

 to me in which wider skill in the methods of bacteriology, biologi- 

 cal chemistry, and colloidal chemistry are required. A group 

 of investigators attacking such a problem and conferring in 



