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nation. In the latter department the activity of microscopists has been of 
late so great that the task of selecting useful apparatus and processes from 
the multitude of things recommended with more or less reason in every 
publication devoted to the interests of microscopists, must have been no light 
task ; and although it is quite possible that Dr. Carpenter may have omitted 
some details that might put in a claim to notice, his book is in this depart- 
ment wonderfully up to date. We notice many things, especially in the 
way of apparatus, which seem to have been only just brought before the 
microscopic world. 
In this edition some little notice is given to the important applications of 
the microscope in geological, and especially in petrological investigations ; 
want of space, probably quite as much as the necessity for special minera- 
logical knowledge on the part of the reader, inducing Dr. Carpenter to cut 
what he has to say upon this department of his subject very short indeed. 
Considering the extent to which petrology is pushing into the front of geo- 
logical research in the present day, one would be glad to see its principles 
treated at somewhat greater length in such a book as this of Dr. Carpenter’s ; 
at the same time, his brief statement, accompanied as it is by references to 
works in which the student may find further information, is always a step 
in the right direction. 
FLOATING GERMS.* 
I N view, probably, of the meeting of the International Medical Congress, 
which has recently been held in London, Prof. Tyndall has collected, in 
a small octavo volume, some half-dozen of his memoirs on the floating par- 
ticles so abundant in the air, and which he has made out to play so important 
a part in many ways. We have here the full description of those numerous 
and elaborate experiments which the author made for the purpose of demon- 
strating the organic nature of some of the constituents of the atmospheric 
dust, and their influence in producing putrefaction associated with the 
growth of Bacteria in organic infusions, experiments which have always 
seemed to us to prove most satisfactorily the thesis which the author had 
set before him. Indeed, the experiments of Pasteur, which now date back 
a good many years, would, one might think, have been regarded as con- 
clusive. 
Nevertheless, the doctrine of spontaneous generation still retains a certain 
amount of vitality, and Dr. Bastian especially maintains it with great 
vigour. This doctrine, and the arguments of its supporters, are discussed at 
considerable length by Prof. Tyndall in more than one of these papers, and 
it seems to us that he has fully demonstrated its untenability. The coup 
de g race seems to be given to all arguments in its favour, founded upon 
assumed imperfections in the result of previous experiments of its opponents, 
* Essay 8 on the Floating matter of the Air in Relation to Rutref action 
and Infection. By John Tyndall, F.R.S, 8vo. London : Longmans, 1881. 
