746 
Journal of Agricultural Research 
Vol. V, No. 16 
In the above table the sugars and other carbohydrates are arranged on 
the basis of vigor of vegetative growth. In the main the results of the 
former experiment are substantiated. The strongest growth took place 
with the highly soluble sugars, and the dishes were filled with small ball-like 
masses. The strongest growth was not associated with pycnidia produc¬ 
tion, but on the contrary was opposed to it. At first glance the law of 
Roux and Linossier (1890) seems operative, for pycnidia appeared in 
the carbohydrates, which are known to have extremely high molecular 
weights. But this superficial agreement is abundantly contradicted by 
the first part of the list. Without regard to molecular weight, these 
sugars gave approximately the same growth form, and the variation in 
amount of growth was not striking. It will be noted that these sugars 
are highly soluble, while those toward the bottom of the list are almost 
insoluble. In the one case every bit of the foodstuff was available, while 
in the other only a slight amount of the carbohydrate was open to appro¬ 
priation. The preceding experiment with filter paper and sugars proved 
that, where the scant available carbohydrate of filter paper allowed 
pycnidia production, the addition of sugars destroyed the balance 
between growth and reproduction, and only growth took place. The 
same general relations exist between the members in this table as existed 
in the former experiment. It is worthy of note that Roux and Tinossier 
(1890) and later Hiekel (1906) drew their conclusions from carbohydrates 
such as the first seven. We can find in their method of work the source 
of their error. Their solutions were made up on a percentage basis, and 
where they drew a conclusion that a complex sugar like maltose in 1 per 
cent solution gave a more complex growth than a 1 per cent glucose 
solution, because of the difference in molecular weight, they were in 
reality comparing M/36 and M/i8 solutions, and their conclusion really 
applies to concentration. They had previously shown that a low con¬ 
centration would call out more complex growth forms. 
The cause of the variation in growth among the various sugars is not 
known. A great many factors undoubtedly enter. Nearly all the sugars 
used were split in approximately the same way by the various specific 
enzyms of the organism. Differences in absorption rates, in rapidity 
of enzymotic action, etc., may enter and be responsible for the differences 
in growth here recorded. It may further be remarked that although the 
sugars used were of the highest purity they vary in their relative freedom 
from contamination, owing to difficulties in separation and purification. 
The colloidal carbohydrates undoubtedly carry a mass of adsorbed 
material, while in the others, traces of calcium, nitrogenous material, 
etc., may be present. It is not unusual to find a minute gummy scum 
on freshly prepared maltose solution. 
Certain other interesting points are to be found in the table. The 
production of the growth form called “oidia”—multiseptate, heavy- 
walled hyphae resembling Dematium or at times Monilia—were constantly 
