SCIENTIFIC SUMMAET. 
421 
external conformation and the internal structure of the organ. The paper 
is too long for abstract, but it seems that M. Lestiboudois makes out a good 
case. The illustrative examples are numerous and appropriate. The fol- 
lowing conclusion terminates the memoir : — The bundles (woody bundles ? ) 
in many of the cucurbitaceae have the peculiar arrangement of foliar expan- 
sions ; these divisions are strikingly like the disposition of the veins of 
palmate leaves. These characters undergo modifications, but they are never 
as great as those seen in the petiole itself. Hence it seems right to conclude 
that the tendril represents a leaf produced by an axillary branch. Vide 
Comptes Rejidus, August 10. 
Ml) coderma Cervisia^.—Yn an important paper on the development of the 
yeast of beer, M. Tr^cul publishes some very interesting facts concerning 
the relation which exists between apparently different species of the lower 
fungi. M. Trecul concludes that there is a specific identity between the 
yeast of beer and the Mycoderma cervisice. It appears to him most likely 
that the yeast of beer invariably commences its existence by cells of this 
mycoderma. In the same number of the Comptes Rendus (August 10) in 
which this paper of M. Trecul is published there is also a communication 
from M. Pouchet. The advocate of Heterogeny claims the priority of the 
observations reported above. He states that M. Trecul has fully confirmed 
all that he has already published in his work on spontaneous generation. 
He, however, differs from M. Trecul in reference to the statement made by 
the latter, to the effect that the yeast rapidly spreads by budding. This 
phenomenon M. Pouchet denies. He states that one is very easily deceived 
in regard to it, and that he had made hundreds of experiments before he 
was able to demonstrate that the process does not take place. 
The Ripening and R^eaping of Grain. — The question when corn ought to be 
cut so as to secure the heaviest and best grain is one of great importance 
both to the agriculturist and the country. The following quotation from a 
French Journal is therefore of some interest : — Certain agronomists are of 
opinion that there is a great advantage in reaping corn before its complete 
maturity, when the grain is still in a milky state, because then it is more 
yellow, larger, and heavier, and does not so easily fall out of the ear during 
harvest operations ; moreover, the straw is then better for cattle. M. Isidore 
Pierre, professor of chemistry at Caen, has endeavoured to ascertain by 
direct experiment whether there was any sufficient foundation for this 
belief. He accordingly cut from the same field a certain quantity of ears on 
the 6th, Ilth, loth, 20th, and 25th of July, each time operating on equal 
surfaces of ground. The grain gathered on the 6th was in a state of 
rapid increase, while that of the 25th was perfectly ripe, and in course of 
reaping that very day. The result was, that in a state of perfect dryness 
the first lot was to the second as 15 to 27, the other lots being, of course, 
intermediate between the two. Taking the hectare as the unit of surface, 
M. Isidore Pierre arrives at this conclusion: that, during the three weeks 
preceding the harvest, a crop of wheat will experience an average daily 
increase of one hectolitre, the weight of the latter being 81 kilog. Hence, 
for every day corn is reaped earlier than the full period of maturity, there 
is a loss represented by a 20-franc piece or thereabouts per hectare. Chemi- 
cally considered, the grain that has not arrived at full maturity contains less 
