No. 390.] REVIEWS OF RECENT LITERATURE. 539 
as a primitive type, although many botanists will be inclined to 
consider it as a degenerate rather than as a primitive form. 
Of the different types of sporogonium among the Musci the pecu- 
liar genus Nanomitrium is interesting as showing very marked simi- 
larity in the arrangement of its parts to that of the typical liverworts. 
In this moss most of the endothecium appears to be composed of 
sporogenous tissue. Whether this genus, and the similar Archidium, 
are really primitive types, as Leitget supposed, or are related to the 
typical Bryinez, remains to be seen. 
The book is fully illustrated and includes many new figures. It 
is certainly a most important contribution to the literature of the 
archegoniate plants. DHC 
Aldehyde in Leaves.!— The formation of an insoluble “ hydra- 
zone” on the addition of metanitrobenzohydrazide to a solution of an 
aldehyde was taken as a means of the quantitative estimation of the 
latter substance in green leaves. Previously it has been shown by 
qualitative tests that a “leaf aldehyde” (Blätteraldehyd) is found in 
many plants. The quantity present seems to vary within wide limits ; 
the conditions influencing its formation are not understood. From 
the experiments it appears that leaves kept in continued darkness 
show a decrease in the amount of aldehyde present, but by no means 
all of it disappears under such conditions. The bearing of this fact 
on the suggestions that some form of aldehyde is the first product of 
photosynthesis are, however, not distinct at present. But while 
nothing has been shown which proves that such a substance may be 
the initial carbohydrate formed, it is a matter of interest that the 
aldehyde can be utilized by the plant as a food substance, and such 
certainly seems to be the case. It would be of especial value, how- 
ever, to know something of the relation which exists between the dis- 
appearance of starch in the absence of light and the partial use of 
the aldehyde under similar conditions. One might then be able to 
conclude whether it is due to the exhaustion of other reserve mate- 
rial that the plant is perforce necessitated to utilize the aldehyde, 
or whether it exercises any selective power in this regard. The 
writers do not maintain that the aldehyde is to be regarded as the 
first assimilation product, — in fact they directly state that it is to be 
regarded as a by-product; but it is hard to agree with them that had 
1 Reinke, J., and Braunmüller, E. Untersuchungen über den Einfluss des 
Lichtes auf den Gehalt der griinen Blatter an Aldehyd, Rev. d. deut. Bot. Gesel., 
Bd. xvii, Heft 1, p. 7. 
