202 
POPULAR SCIENCE REVIEW. 
under the present ocean. They seem to he conclusive proof of the recent 
encroachments of the ocean upon the shore-line in that vicinity. 
An Abnormal Potato , one growing from the centre of another , was some 
time since presented to the Philadelphian Academy and was reported on by 
Mr. T. Meehan. It had been handed to him by the curators, and on dissec- 
tion, though no exact place of origin could be traced, there seemed nothing 
to indicate any other theory of origin than that one potato had really 
grown out of the centre of the other. But there were serious physiological 
reasons in the way of such a theory. A potato tuber is really but a 
thickened axis, in which the greater part of the interior structure would be 
incapable of developing a bud which would produce a tuber such as this 
one had done. The origin of a new tuber from an old one would be nearer 
the old one’s surface. He had been looking for some further explanatory 
facts, and believed he had them then, in the potato tubers he handed to the 
members. They were about the size of hen eggs, and were pierced in every 
direction by stolons of the common couch grass, Triticum repens. They 
had gone completely through, as if they were so much wire, and in one 
instance two tubers had become strung together by the same stolon, as if 
they were two beads on a string. One would suppose that the apex of the 
'stolon, when it came in contact with the hard surface of the tuber, would 
turn aside and rather follow the softer line of the earth ; but there was no 
appearance of any inclination to depart from their direct course. They had 
gone apparently straight through. He had no doubt the potato before 
referred to was a similar case, a potato stolon had penetrated another 
potato, and instead of going through as these grass spears had done, termi- 
nated in the centre, and formed the new potato there. It was worthy of 
thought whether so much attention had been given to this direct force in 
plants as the subject deserved. It was well known that a mushroom would 
lift a paving-stone many times its own weight, rather than turn over and 
grow sideways, which it would appear so much easier for it to do ; and tree 
roots growing against walls would throw immensely strong ones over, 
though one would think the pressure against the softer soil would give 
room for their development, without the necessity of their expending so 
much force against the wall. 
Culture of various Herbs and Plants. — On October 10, M. Decaisne read 
a paper before the French Academy recommending strongly the advisability 
of cultivating various forms of herbs and plants during the siege. He 
points out that great results would be obtained and that the thing could 
easily be done. 
Structure of Ferns. — The fact that Paris was besieged does not seem to 
have interfered much with the botanists. In the u Comptes Rendus ” of the 
Academy for October 31, we find M. Trecul discussing the ferns as fully as 
ever. In regard to Didymochlcena sinuosa he cites all the old and 
recent authorities from whom he differs, and in this manner occupies 
very nearly nine pages of the Journal. The memoir must be read carefully 
by those interested ; it is much too long for an abstract. 
The Development of the Leaves of Sarracenia. — M. H. Baillon, in a 
memoir presented to the French Academy by M. Brongniart (November 7), 
enters very fully into this subject and discusses the views of Saint-Hilaire, 
