20 BOTANICAL GAZETTE. [ Jan., 
CURRENT LITERATURE. 
House Plants as Sanitary Agents; or, the relation of growing vegetation 
to health and pao comprising also a consideration of the subject 
of practical floriculture, and of the sanitary influences of forests and 
lantations. By J. M. Anders, M. D., Ph. D.,etc. Philadelohia: J. B. 
ippincott Co., 1887. 12°, pp. 334 
Dr. Anders is already known to many of our readers, through his 
papers on this subject in the American Naturalist and elsewhere. The 
present book is an amplification (we had almost said a diffusion) of those 
papers, with suitable changes and additions. The theses of the book are 
that house plants act as sanitary agents by (1) adding moisture to the air 
by transpiration ; (2) producing ozone; (3) by their positive therapeutic 
value in certain diseases; (4) by their appeal to the esthetic side of our 
nature. The latter claim no one will dispute. But it is not clear that 
house plants materially affect the quantity of ozone in the dwelling, nor 
do the experiments of the author at all demonstrate this. Indeed they 
seem to be rather indefinite, and read too much like experiments carried 
on to prove a previously assumed theory. Equally questionable also is 
the therapeutic value of ordinary house plants. The conclusions from 
the facts are not necessary ones, because of the innumerable opportuni- 
ties for the action of other causes. It is well known how difficult it is to 
determine the therapeutic value of a substance administered directly; 
how much more to determine the value of one factor in a patient's” 
environment! 
We may concede the value of house plants in increasing the percent- 
age of moisture in the air of a room, but it is questionable whether the 
effect of forests is appreciable in this direction. Indeed the whole ques- 
tion of the influence of forests on climate must be considered as yet 
problematical. Throughout the book the author has shown himself pos- 
sessed by his subject, and he has ransacked every nook and corner to 
find support for his main idea. The reader must, therefore, estimate for 
himself the relative values of the authorities quoted, and must take with 
a grain of allowance many of the deductions. 
Aside from slack proof-reading, the book is well manufactured. 
Zur Systematik der Torfmoose, von Dr. Julius Roll in Darmstadt. Separat- 
Abdruck aus Flora, 1885, 1886, 8°. pp. 108. 
We have already noticed the 
in Flora (see this journal, 1886, 
pamphlet form, and 
ber, describe the ori 
p. 127). It now appears as a reprint in 
from it may not be confused by this alteration. : 
The author first establishes what can hardly be controverted, viz 
the 
great variability of the characters used for specific distinctions, and 4 
a ale 
"a 
publication of this work as it appeared — 
unfortunately re-paged. We shall, in the next num- | 
original paging, so that those who have occasion to quote 4 
