950 
will prove that, as Wormser claims, iodo- 
thyrin is not the only active body secreted 
by the thyroid, but that some other sub- 
stance must act with it in order to perform 
all the functions of the gland. 
Wormser’s experiments were carried out 
upon dogs whose thyroids had been care- 
fully removed. The animals were fed with 
various preparations made from thyroids as 
well as such artificial compounds as sodium 
iodide and iodo-casein, and the influence of 
these substances, in preventing or lessen- 
ing the tetanus and other symptoms re- 
sulting from the operation, was noted. 
The first animal experimented upon was 
fed with dry thyroids for twenty days after 
the thyroidectomy, and during this time its 
condition showed nothing abnormal. On 
the twenty-first day the dry thyroids were 
replaced by iodothyrin in such quantity 
that the iodine content equaled that of the 
previously administered glands. Two days 
later the animal was seized by a violent 
tetanus. The dry thyroids were again ad- 
ministered, and the dog recovered in a few 
hours. The glands were again replaced by 
iodothyrin, and the animal died within 
thirty-six hours. This experiment was re- 
peated three times with iodothyrin prepared 
from sheep and pigs by both of Baumann’s 
methods, and the results agreed perfectly. 
Todo-casein, an artificial compound, has 
been found efficacious in reducing the size 
of a goitre. When this substance was ad- 
ministered to dogs whose thyroids had been 
removed, the intensity of the tetanus seemed 
to be reduced, but death nevertheless en- 
sued. Similar experiments were tried with 
sodium iodide, and with the albuminous ma- 
terial precipitated from a sodium chloride 
extract of the thyroid gland by acetic acid. 
These results, however, were entirely nega- 
tive. 
Wormeer notes, however, that throughout 
these investigations he found young animals 
far more susceptible to the evil effects of 
SCIENCE. 
[N.S. Von. VI. No. 156. 
thyroidectomy than fully mature or old ani- 
mals, while the appearance of tetanus and 
other symptoms was delayed by a milk 
diet, but hastened by one largely composed 
of meat. 
Finally, in summing up the results of his 
experiments, Wormser points out that the 
thyroid itself or an aqueous extract of the 
gland is far more potent physiologically 
than any substance yet isolated from the 
gland or artificially prepared, and that there- 
fore no one substance can account for all 
the functions of the thyroid. 
YANDELL HENDERSON. 
THE ENZYMIC FERMENTS IN PLANT PHYSI- 
OLOGY. 
FERMENTATION, as a general term, covers 
many of the most important processes in 
chemistry. Fermentations are of many 
particular kinds, each depending more or 
less distinctly upon some specific ferment 
agent. This makes it convenient to classify 
the fermentation processes according to the 
correlated ferment agents. Thus we have 
yeast fermentation, bacterial fermentation, 
enzymic fermentation and the like. 
The ferment agents, and, following them, 
the fermentation processes, may be roughly 
thrown into three classes: (1) Those be- 
longing to the lower orders of fungi, like 
yeast. (2) Bacteria, like those present in 
the ‘mother’ of vinegar, or in the souring 
of milk. These two classes are often called 
organic ferments in distinction from the 
next. (3) Unorganized, or soluble fer- 
ments, or enzyms, like diastase, pepsin and 
ptyalin. The knowledge of these enzyms 
is mostly of very recent development, and 
is still fragmentary and generally unsatis- 
fying. They have been best known as they 
occur in the animal digestive juices. The 
students of animal physiology have been 
used for some years to point out the pres- 
ence of ptyalin and diastase in saliva, of 
pepsin and trypsin in the gastric juice, and 
