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POPULAR SCIENCE REVIEW. 
to be inserted one upon tbe other. Again^ he explains the adhesion of the 
ovary by assuming the original coalescence with all the floral whorls which 
are external to it ; a coalescence of the same kind as that which unites the 
separate carpels into the compound pistil, or the petals and stamens into the 
monopetalous corolla. The Academy’s commissioners do not quite concur in 
the opinions of M. Aan Tieghem, but they think his conclusions worthy of 
all attention, and regard them as at least extremely ingenious. The me- 
moir extends over 200 pages, and is illustrated by an atlas containing 500 
carefully-drawn flgures, illustrative of the plants examined, and of the dis- 
sections. The commissioners were MM. Brongniart Tulasne, Duchartre, and 
Trecul, and the reporter M. Decaisne. As showing how carefully the French 
conduct their awards of prizes, we may mention -that the commissioners 
repeated several of M. Van Tieghem’s dissections, and found his statements 
absolutely correct. — Vide Comptes Rendus, May 18. 
Cellulose a Tissue. — Some very recent researches of M. Payen demonstrate 
the existence of cellulose as a distinct tissue, which, by careful chemical and 
physical operations, may be extracted from surrounding tissues of the plant, 
and examined under the microscope. The plant he first experimented on 
was the potato, the tubers of which he submitted to a process of freezing. — 
Comptes Rendus, tom. LXVL, No. 11. 
The Vessels of the Musacece. — M. Trecul, with so many of whose re- 
searches on the vascular system of plants our readers are now familiar, has 
published a memoir on the above subject, in which he describes the situa- 
tion and characters of the proper vessels in several genera of this family. 
He concludes that the Musacece, like the Rapaveracece, present proper vessels 
of variable construction, but that the former have them in a less degvee than 
the latter. M. Trecul’s paper was presented to the French Academy on 
March 18. 
Nexo Botanical Works. — Among the many botanical treatises published of 
late, we may call attention to the following ; — Sur la Floraison de la Vigne, 
by M. Henri Mares : Montpellier, Les Coniferes Indigenes et Exotiques, by 
M. de Kerivan : Paris, 2 vols. with plates. E Art des Jar dins, by Baron 
Ernouf: Paris. Botanique, Cryptogamique, etc., par M. J. Payer, 2nd 
edition : Paris, 1868. 
The Increase in Width of the Stems of Dicotyledons. — M. G. Colin has 
been following up the well-known researches of Duhamel, but he has been 
adopting a method of his own. Instead of inserting metallic plates under 
the bark, he has placed them in the thickness of the liber, and in this way 
he has experimented on the mulberry, the oak, the sycamore, and various 
members of the family Rosacece. He laid down the following questions for 
reply: — (1.) Are the new woody layers of Dicotyledons formed from the 
exterior of the older, and from the transformation of some of the elements 
of the liber, or are they the result of the formation of new elements in the 
developing (cambium) layer ? (2.) In what order and manner is the de- 
velopment of the new layers accomplished ? In regard to the first point 
he makes the following important remarks ; — Experiment proves that the 
woody layer proceeds neither from the extension of the subjacent sap (?) 
nor from any modification of the elements of the liber, although, in the 
absence of the generative zone, the liber on the one hand, and the sap on the 
