REVIEWS. 
409 
matter is general, but, so far as possible, confined to man. That is to say, 
that the different writers treat upon the subject of human histology, and 
bring in comparative facts whenever there seems a necessity for them. 
To the medical man especially, the several chapters will be of especial in- 
terest, since they bring up the knowledge of the subject to the latest (or 
nearly so) date. But the first chapter is one which every microscopist 
would do well to read. It deals with the subject of microscopy, and re- 
counting objects and the different applications of electricity, gas, &c., which 
have been made of late years by men like Recklinghausen, Strieker, 
Deville, Kiihne, Schultze, and Briicke. It forms a kind of introduction, a 
preparatory chapter to the work, and is, we believe, from the pen of Herr 
Strieker himself. The remainder of the work, extending over exactly six 
hundred pages, deals with cells, connective tissues, nervous tissue, organic 
muscles, relation between ultimate fibres of nerve, muscles, muscle under 
the polariscope, the heart, blood-vessels, lymphatics, spleen, thyrus, thy- 
roid, blood, salivary glands, teeth, the whole alimentary and intestinal 
canal, and, lastly, of the blood-vessels connected with the alimentary canal. 
In each case the most recent views are given, and the volume is full of 
interest to those to whom it has any interest. We cannot speak too 
well of Mr. Power’s efforts as a translator. He has had a difficult task 
to perform, and he has done it admirably well. 
ON HEAT.* 
W E see, with not a little satisfaction, that this work has actually gone 
through four separate editions since the year 1863, and so far we 
have every reason to be satisfied. It must be confessed that it is the only 
work which the English student finds convenient. But this is not all ; it 
is carefully brought up in each edition to the state of actual knowledge of 
the time, and even the present edition contains matters and facts not to be 
found in any of the earlier issues. 
It will be well, therefore, if we pay attention to some of the more 
striking of the novelties which the present volume possesses over its 
predecessors. Firstly, we have in this the relations of gaseous matter to 
the shorter waves of the spectrum. Then comes the consideration of the 
blue of the sky and the polarisation of its light j and, lastly, we have the 
hypothesis regarding the constitution of comets, or the polarisation of heat. 
Perhaps of all these the sky-question is at once the most generally 
interesting and practicable of all. We shall endeavour to follow the 
professor’s description, though it is a little difficult, because of the space at 
our disposal to do so. Having described fully a small tube filled partly with 
nitrate of amyl, and peculiarly connected, he goe3 on as follows : u Opening 
the cock cautiously, the air of the room passes in the first place through 
* “ Heat a Mode of Motion.” By John Tyndall, LL.D., F.R.S., Pro- 
fessor of Natural Philosophy in the Royal Institution of Great Britain. 
Fourth edition. London : Longmans, 1870. 
