1904] CURRENT LITERATURE 233 
but soon becomes reduced. ‘The fusions resemble sexual fusions in the behavior 
of the chromatin. The nuclear fusion and the reduction may be regarded as 
automatically regulated phenomena. Reduction may sometimes be an atavistic 
er; it is a result of fusion rather than a preparation for it. Morphologically 
the most important character of fertilization lies not in nuclear fusion but in cell 
fusion. When the conditions for cell fusion are present the other phenomena 
(under certain conditions) follow necessarily as automatically regulated pro- 
cesses.—CHARLES J. CHAMBERLAIN. 
Tue extant theories of causality in leaf arrangement have been critically 
discussed in detail by WivKLER*° in two parts of a paper on this subject, of 
which we are promised a continuation in a third part. The author brings for- 
ward evidence from various plants that the mechanical theory of SCHWENDENER 
will not suffice to explain the formation and development of primordia. There 
appear to be many cases in which the primordia are not constant in size at the 
start, many in which contact or absence of contact between different primordia 
plays no controlling réle in development, and also many in which pressure of older 
parts has no influence. The various theories of teleological nature, such as the 
common one which attributes leaf arrangement to the need of having these organs 
so placed as to give best access of air and light, are discussed rather more fully 
than would seém necessary for intelligent readers. It is to be hoped that such 
theories may at length be accorded a decent burial and then allowed to rest. 
constructive part of this paper points out that any theory of leaf arrange- 
ment which is satisfactory must consider internal factors together with the external - 
ones. WINKLER is careful to indicate that by this term he refers merely to those 
Protoplasmic conditions (probably purely physical) of which we know absolutely 
ing at present except that they exist. The general conclusion of the paper 
i up in a paraphrase of the author’s words, that the formation 
(a t : Big tip is an extraordinarily complex process controlled by 
ina ) actors of different kinds, concerning the nature and influence of 
now practically nothing —B. E. Livrncston. - 
Se oat has just published the results of his study of the date palm, and 
lor Ps hap aeg not only in demonstrating the possibilities of a valuable crop 
ed States in regions otherwise apparently hopeless from an agricul- 
St a Ww, but also from their much larger practical bearing upon the 
dispute it? tap The following statement is vigorous, but who will 
ieeld nd the Present it is no exaggeration to state that the life history require- 
are far better sn . the power to resist unfavorable environmental conditions 
and tein own for many microscopic lower plants, such as bacteria, fungi, 
———_” “Ven for species having no economic importance, than for the most 
a)” H., So micanigen zur Theorie der Blattstellungen. I. Jahrb. 
sian “igh §- 4. 1901; IT, ibid. 501-544. pl. 1. 1903. 
PP. 155. pls. 22, Sy date palm and its utilization in the southwestern states, 
* #1. Industry, U. S. Dept. Agric., Bulletin 53- April 28. 1904. 
