RECENT LITERATURE. 
E. STRASBURGER: Histologische Beitrage, Heft. iv. Ueber 
das Verhalten des Pollens und die Befruchiungs—vorgauge 
bet den Gymnospermen. Schwirmsporen, Gameten, pflanzliche 
Spermatozoiden, und das Wesen der Befruchtung.—Jena, 1892. 
As new facts are brought to light we are constantly obliged to 
alter our views. Nowhere is this truer than in regard to the 
structure and functions of the plant-cell. With the marvelous 
advances made in histological methods, more and more accurate 
information concerning the minutest details of cell-structure is 
being brought forward, and this frequently involves material 
changes in statements hitherto unchallenged. ; 
The extremely interesting and valuable work before us illus- 
trates this most strikingly. Probably no living botanist has con- 
tributed so much to our knowledge of the plant-cell as Stras- 
burger, and any statements that come from him on this subject 
bear the stamp of authority; yet in the present work he has found 
it necessary to modify very substantially some of his earlier pub- 
lished statements. ‘The work was evidently inspired largely by 
the recent remarkable discoveries of Guignard, and to some 
extent also by important researches by Belajeff. 
The volume before us is divided into two parts; the first deals 
with the development of the pollen and the process of fertilization 
in Gymnosperms; the second, with a comparative study of the 
zoospores of algee and spermatozoids, and studies in fertilization 
in various groups of plants. 
Until very recently it was supposed that in the Gymnosperms, 
with the exception of the Cycads, that but two cells were formed 
in the ripe pollen-spore, and that the nucleus of the larger one 
which forms the pollen-tube, was the direct agent in fertilization. 
Belajeff* demonstrated that in 7a«us it was the smaller cell that 
represented the fertilizing element, and Strasburger now finds 
that this is true also in other Gymnosperms. He also finds that 
in a number of forms examined, e. g., Larzx, Picea, Pinus, 
Ginkgo, that three cells are successively cut off from the body of 
*“Zur Lehre von den Pollenschlauchen der Gymnospermen.” Ber. 
der Deutschen botanischen Gesellschaft—1891—Bd. ix, p. 280. 
