452 Scientifie Intelligence. 
became requisite to take account of the plants of higher rank, and of 
the various organs which these possess. ‘The treatise, therefore, con- 
tains, if an imperfect, still in many respects, a more extensive resumé 
of Vegetable Physiology, than might be conjectured from the title. 
“ Unhappily, the Physiology of Plants is a science which yet lies in 
its earliest infancy. Few of its dogmas can be regarded as settled be- 
yond doubt; at every step we meet with imperfect observations, and 
consequently with the most contradictory views; thus, for example, 
Opinions are still quite divided regarding the doctrines of the develop- 
ment of the cell, of the origin of the embryo, and of the existence of 
an impregnation in the higher Cryptogams. Both in these and in other 
cases, the small compass of the present treatise forbids a more exlen- 
sive detail of the researches upon which the opposing views are foun- 
ded; I hope, however, that I have succeeded in making clearly prom- 
inent the chief points upon which these contests turn, and thus in facil- 
itating the formation of a judgment by the reader; and I have never 
neglected to indicate the literature from which further instruction is to 
be derived.”. ; 
It may be well to notice the views of so excellent an observer upon 
the view that considers them as intercellular passages which have ac- 
quired membranous linings. (p. 2.) He denies that the membrane 
nascent cells is soluble in water, as Schleiden states. (p. 9. e brief- 
ly states the grounds on which, in his controversy with Harting and 
Mulder, he successfully maintains that the primary cell-membrane is 
thickened by successive concentric layers of cellulose deposited on its 
inner face. ‘The combination of spiral markings and pits on the wood- 
cells of Taxus and Torreya, as also in the Linden, is explained by con- 
sidering the former to belong to a second layer or deposition, within 
that to which the pits belong. This tertiary membrane or deposit forms 
the spiral fibre or band in the cells of the seed-coat of Collomia, the 
hairs of the achenium of Senecio, &c. (p. 18.) The whole subject — 
the chemical reactions of cellulose, but which may be removed by pre 
Vious maceration in caustic potash and nitric acid. He now maintaiDs, 
in opposition to his early view (still defended by Schleiden) that the 
ntercellular substance is a product or secretion of the cell, and mgd 
rsally distributed mass in which the cells are imbedded. (p- 33:) 
shows that the thickened ‘ cuticle” of Unger, Mulder, Harting, &- 
; ai layers of cell-membrane, deposited from the in 
w 
phy 5 
