SCIENTIFIC SUMMARY. 
315 
published the results of a series of analyses and experiments, which demon- 
strated beyond all question that the weakness of the stalks of corn — so 
fertile a source of injury to the farmer — is not due to the absence of silica. 
This is merely, however, a corroboration of the conclusion already arrived 
at by M. Isidore Pierre. But M. Velter’s inquiries have been pushed 
further. He has found not only that a supply of silicate of potash to the 
growing plant renders the stem less able to resist the effects of the wind, 
but that the cause of weakness is a want of general nutrition, an absence of 
the proper quantities and proportions of all the elements which enter into 
the composition of the stem. His paper contains several interesting tables, 
and it concludes as follows : — If corn is blown down, it is not because it 
wants silica — which, by the way, is always present in the free state — but 
because owing to want of air or light, or want of development of the woody 
matter, the lower part of the stem has not undergone its proper develop- 
ment. The base of the stem is etiolate and incapable of supporting the ear. 
Giving it light, and sowing the corn in trenches, are the best means of 
preventing breakage. 
The Corpuscles found in diseased Silk-worms . — A discussion has taken place in 
Paris relative to the nature of these bodies and to their mode of reproduction. 
MM. Pasteur and Bechamp contend that they are reproduced hj fission and 
that they have seen the several stages of .the phenomena. M. Balbiani, 
however, disputes this view and gives the following objections to M. 
Pasteur’s observations : (1) The bodies examined by M. Pasteur may have 
been extraneous, and not related to the so-called pebrine corpuscles. (2) 
They may have been abnormal bodies produced by the union of two or more 
ordinary corpuscles which thus simulated a reproductive condition. It is not 
easy to see why MM. Pasteur and Bechamp should have fallen into error 
in this instance. At all events Mr. Balbiani’s objections might be urged 
against even the admitted instances of fission in organisms. 
Photographs of fossil plants. — A splendid series of photographs representa- 
tive of the flora of the coal measures has been sent to the Paris Exhibition by 
Herr P. Goeppert, who is certainly one of our first European authorities on 
the subject of coal-fossils. The photographs, 29 in number, are from the 
typical plants of the Silesian coalfield, and are of the natural size. As the 
species photographed are common to England and Silesia, there is a fine 
opportunity for English palaeontological students. 
Silicifed vegetable remains from Zambesi . — Some mud brought from the 
Zambesi by Mr. Baines has been examined by Hr. John Lowe, who boiled it 
in nitric acid and liquor potassse, and found it to consist of vegetable cells 
perfectly silicified and mixed with numerous diatomaceee. Dr. Lowe has 
described the various forms met with. 
The plants of Iceland. — Under this title Mr. Isaac Carroll has a paper in 
the Journal of Botany for April. He gives a long list of the plants found. 
He is convinced that a few weeks or months spent in the North or North- 
west part of the island would yield a rich harvest to the careful botanist. 
The most remarkable feature in the Iceland flora appears to be its strikingly 
Arctic character, shown by the absence of trees and the occurrence near the 
sea-level of plants which in Norway and Lapland are -found at considerable 
elevations. The number of lichens is small, the lava appearing generally 
