418 
Analyses of Books. 
[July, 
ary organs of animals which Nature has suppressed and super- 
seded, and which only tell of uses long since passed away.” 
Commenting on the custom of salutation by rubbing noses 
together, as common among not a few savage tribes, Mr. Massey 
reminds us that it “ goes back to the animal mode of salutation 
by smelling.” In this direction he has done good service in 
connecting the language and customs of animals with those of 
man. 
Reluctantly breaking off our survey of this remarkable, book, 
we can merely hope that what we have said may at least excite 
the curiosity of the reader, and lead him to inquire for himself. 
We would, indeed, bespeak for Mr. Massey’s work the earnest 
attention of Evolutionists. To us it seems that he is turning 
the only position of importance still held by our opponents, and 
that his movement, if properly followed up, will be decisive. 
A Manual of Photographic Chemistry , Theoretical and Practical. 
By Rev. T. Frederick Hardwick, M.A. Edited by J. 
Traill Taylor, Editor of the Photographic Times and 
American Photographer. London : J. and A. Churchill. 
This work, having already reached its ninth edition, maybe 
considered as having established itself in public favour. The 
present editor tells us that, since the appearance of former edi- 
tions, two changes of importance have occurred. One of these 
appears to be the last revolution in chemical nomenclature ; the 
other, of a practical nature, is the introduction of a gelatine 
emulsion in place of collodion. He accordingly uses in the work 
an approximation to the modern nomenclature, though remarking 
that it does not seem judicious entirely to discard the old. This 
caution is justified by the fact that manufacturers, drysalters, 
and persons practically engaged in the various chemical arts, 
still employ almost exclusively the language current in the second 
quarter of the present century. Perhaps, however, his best plan 
would have been to have placed the old names in brackets after 
the new ones, or inversely. 
A few errors appear to have escaped the notice both of author 
and editor. Thus, under “ Alum,” we find the statement that 
“ much of the common alum contains ammonia as well as potas- 
sium.” There was at one time a great abundance of so-called 
ammonia-alum in the market in which ammonium took the place 
of potassium. But we never either heard of or met with a sample 
in which both these bodies were simultaneously present. Since the 
discovery of the Stassfurt saline deposits the salts of potash have 
