DECEMBER 24, 1897.] 
of pancreatin, trypsin and diastase in the 
pancreatic secretions. And in a very hazy 
sort of way it has been known for a con- 
siderable time that the same and similar 
ferments are active in the physiological 
processes of plants. In very recent years 
the sharp press of experiment upon all 
phases of plant economy has brought to 
light many facts of almost startling interest. 
We may reasonably hope to collect obser- 
vations enough within a few years to make 
generalization practicable; but up to the 
present we are doing fairly well to get some 
detached notions of certain of these enzyms, 
of their nature and action, and their rela- 
tion to important vegetation processes. 
The certain determination, even qualita- 
tively, of all the enzyms present in any 
given part of a plant can hardly be safely 
made in any case ; but it is known that vari- 
ous enzyms are present in nearly all the 
living organs. Hach plant—especially 
among the flowering plants—takes up 
quantities of food materials, which it circu- 
lates, digests, stores, unstores, circulates 
again, assimilates, breaks down and finally, 
perhaps, excretes. In all the multifarious 
processes of digestion and redigestion the 
enzyms may take prominent part. They 
are almost always found in connection with 
special food storages, as in buds, tubers, 
bulbs and seeds. 
Before a healthy deciduous woody plant 
enters upon its period of rest it stores up a 
considerable quantity of food with which 
to begin work again in the spring. These 
storages are largely of starch, and may be 
demonstrated by the iodine stain under a 
lens in the woody tissues of stems, es- 
pecially near buds, or in the roots. The 
regions of fruit buds in such plants as 
apple and plum commonly show remark- 
able storages of this sort. With returning 
spring, before the roots start or before the 
leaves are put out to capture and digest 
food, these stores of starch and other ma- 
SCIENCE. 
951 
terials are put in motion once more, and 
from them the new leaves are built or the 
early blossoms pushed forth. Theoretically 
and from experiment we are led to believe 
that these early redigestive processes are 
dependent on certain enzymic ferments. 
In a quite similar manner those plants 
which propagate their species by means of 
tubers or bulbs store quantities of food in 
such organs which later can be reabsorbed 
and used to start the young plantlet. The 
recent remarkable results reported by 
Johanssen before the Agricultural High 
School of Copenhagen, and so liberally 
noticed in the public prints of America, 
were brought about by the application of 
ether fumes to secure an early liberation of 
these stores of food in bulbs and dormant 
woody plants. 
Seeds act in the same way. When per- 
fectly ripe and viable seeds are brought 
into conditions favorable to germination, 
the relatively large stores of food which 
they contain are released for the use of the 
nascent plant. In this case the activity of 
diastasic ferments is comparatively well 
known. Perhaps other enzyms are also 
present and active. The chief commercial 
source of diastase, in fact, is malt, that is, 
grain taken at the height of the germina- 
tion activities. It has been often observed 
that seeds do not germinate well if planted 
immediately after ripening; that a period 
of rest increases the promptness and vigor 
of germination; and it has been thought 
probable that this period of rest is useful 
in allowing the accumulation of the neces- 
sary enzymic ferments. 
One of the facts of commonest knowledge 
is that seeds deteriorate in viability when 
kept for some time. The period at which 
all the seeds of a sample lose their power 
of germination varies from two to twenty 
years or more, but most garden seeds de- 
teriorate rapidly after they are three years 
of age. It has seemed probable that this 
