538 
Experimentation in Biology. [September, 
reflection from surrounding objects. In the section on the 
accommodation of water-breathers to breathing air, reference 
is made to the experiments of Jobert on the swimming- 
bladder of fishes, and, elsewhere, to those of Moreau and 
Jouriet. Some highly-valuable experiments by the author 
are detailed, entailing great inconvenience upon frogs, 
whereby it was established that a solution of i per cent of 
salt in the vessel of water tenanted by the animal was with- 
out any effeCt upon it : this was ascertained by observing 
that a frog so situated lived as long as one placed in fresh 
water ; it was found that twice that percentage proved fatal 
in seven hours, and so on : by tying the animals to sticks in 
a special manner swallowing water was prevented, and of 
course the animals died of starvation in those cases where 
fatal osmotic aCtion had not supervened. Claude Bernard 
and Paul Bert have made experiments in the same direction. 
But the main feature (for our present purpose) of Prof. 
Semper’s volume is not the individual importance of the 
experiments given, these being comparatively insignificant 
from a zoophilist point of view, as the especial experimental 
character of the subject according to the views of the 
author; thus no less than (literally) a score of timesMoes 
Prof. Semper lament the absence of experiment, suggest 
practical investigations on certain lines, complain about the 
prevailing fashions in modern zoology, the insufficiencies of 
our laboratories, and the forcing of Physiology too exclu- 
sively into the service of Medicine : he distinguishes a 
Physiology of Organs and a Physiology of Organisms , and 
thus (in part) anticipates Prof. St. George Mivart, to whom 
Biology owes gratitude for the most happy introduction of 
the term “ Hexicology.” 
The announcement, a few years ago, as a “ forthcoming ” 
volume in the same series as the work of Prof. Karl Semper, 
by Paul Bert, on “ Forms of Life and other Cosmical Con- 
ditions,” warranted the anticipation of an original and 
masterly essay in this department, for M. Bert is well known 
to be experimentally acquainted with the Vertebrata from 
fish upwards, while he has not despised Invertebrates as low 
as Infusoria, but, judging by subsequent catalogues, this 
hope must be abandoned. But this circumstance and the 
fadb that so few severe experiments are recorded in Prof. 
Semper’s volume do not imply that little has been or may 
be done in the investigation of conditions and their influence. 
To renew the case of food, for example, Spallanzani accus- 
tomed a pigeon to meat, an eagle to a diet of bread. 
Voluntary change of diet occurs sometimes in Nature, 
