REVIEWS. 
185 
have to ask, is it possible that no aperture existed in the flask ? and to this 
the author says no, for on applying the blow-pipe it was found that the 
glass was drawn in, there of course being therefore “ a partial vacuum ” 
previously. This may be, but of course one knows how readily glass would 
be blown in by the blowpipe even if no vacuum were there. However, we 
let that pass. Then there arises the question, How soon after the flasks were 
opened were their contents examined ? We assume that it was immediately 
after they were exposed to the air, but the author does not state so. 
Then again, when were the drawings made ? was it immediately, or was it 
some time after? These all appear small questions, but they have a 
considerable importance. Lastly comes the most important query of all. 
How do you know that your temperature was sufficient to destroy life P We 
are aware that Dr. Bastian will reply, “ Because I find that a lower tempera- 
ture was sufficient to destroy those very minute animals — those monads which 
had been developed in the flask.” But then we would inquire, How do you 
know that you destroyed by your application of 230° Fahr. for about an hour 
not only the parent bacteria and other fully developed organisms, but like- 
wise the young offspring of these ? That is the point on which we think 
Dr. Bastian’s argument is weakest. He may have destroyed the parent 
organisms, but how does he know that he also destroyed their germs. For 
we know that they will — from analogy — tolerate a higher temperature than 
their parents without undergoing the slightest injury. So far as we can 
see, Dr. Bastian has made one point in his favour, but it is a very slight 
one, and it must be further developed before we shall be content to believe 
in his hypothesis. 
A NEW MODE OF LEARNING PHYSICS.* 
W HETHER the plan proposed in the present volume is likely to be a 
successful one, time can alone disclose. But that the scheme is one 
which we can highly commend is altogether unquestionable. The book is 
upon experimental physics, but they are taught after a fashion perfectly new in 
this country, and which we trust may prove in the highest degree successful. 
It is at once a book in which are combined the knowledge to be derived 
from the lecture-room with that from the purely physical laboratory. Pro- 
fessor Weinhold, of the Royal Technical School at Chemnitz, has been at 
great pains to construct a book so that the student shall not only learn the 
principles of the science, but shall have the opportunity of putting all those 
principles into practice. This is done by first explaining the scientific facts 
and then showing the reader how he may set to work to put the ideas he has 
learnt into force. Of course, in order to work properly at such a book as 
* u Introduction to Experimental Physics, Theoretical and Practical, in- 
cluding Directions for constructing Physical Apparatus and for making Ex- 
periments.” By A. F. Weinhold, Professor at the Royal Technical School 
at Chemnitz. Translated and Edited by B. Loewy, F.R.A.S., with a Pre- 
face by Professor G. C. Foster, F.R.S. ; illustrated by three coloured plates 
and 404 woodcuts. London : Longmans, 1875* 
