39° BOTANICAL GAZETTE [NOVEMBER 
in their ramifications through the tissues of the host plants? Who 
has solved the chemical and enzyme relationships which may exist 
between these fungi and their hosts? If the insect cecidia are the 
result of chemical stimuli, how about the myco-cecidia? If the 
insect cecidia are due to mechanical irritation, how about the myco- 
cecidia? If the insect cecidia are the result of irritation applied to 
the formative cells, is the same thing true for the myco-cecidia ? 
By what school of biologists should these problems be worked ? 
Will not the solution of one set help in the solution of others? — 
The writer is not presenting these questions for the purpose 
of controversy, but merely to call attention of students to this 
enormous field of plant pathology and plant physiology. Give 
us more data concerning the relationship between parasite and host 
plant, regardless of the character of the parasitic organism. Let 
us tear away the artificial barriers and give the broadest study to 
these problems. 
DELAWARE AGRICULTURAL Hse STATION 
NEWARK, DELAWAR 
