368 REVIEWS — A HISTORY OF INFUSORIA. 



A History of Infusoria, including the Desmidiaceae and Diatomaceae, 

 British and Foreign. By Andrew Pritchard, Esq., M.R.I., author 

 of the " Microscopic Cabinet," &c. Fourth Edition, enlarged and 

 revised by J. T. AWdge, M.B., B.A., Lond. ; W. Archer, Esq. ; 

 J. Ralfs, M.R.C.S.L. ; W. C. Williamson, Esq., F.B.S. ; and the 

 Author. Illustrated by forty plates. London : Whittaker & Co., 

 Ave Maria Lane. 1861. 



This work, in its original form, was the first to make the observa- 

 tions and opinions of Ehrenberg familiar to the British scientific 

 public. It was the first, too, to render accessible to inquirers respect- 

 able microscopic figures of numerous minute organisms with which 

 many become familiar through the microscope. It was found useful, 

 and the author has felt it to be his interest to keep it before the 

 public. The earlier editions contained what are now accounted great 

 errors, at that time universally prevalent, as well as many deficiencies 

 which it is now not difficult to supply. One subject upon which 

 opinion has greatly changed, is the proper limit between the kingdoms 

 of organised nature. What he had previously on high authority 

 described as animals, Mr. Pritchard now sees good reason to regard as 

 vegetables. This change causes him some embarrassment. It is 

 manifestly desirable that the field of his labours should be about the 

 same as it was formerly, yet this now implies its including low forms 

 both of animal and vegetable life, and yet precludes his undertaking 

 a complete investigation of all the lowest groups belonging to either 

 or both kingdoms. His very title, preserved from former editions, is 

 no longer properly applicable. The idea of including Desmidiaceae 

 and Diatomaceae in Infusoria, is somewhat startling, as the latter term 

 has always been employed to express minute microscopic animals ; 

 whilst it is the authors doctrine, in conformity with the general opinion 

 at present, that the two former families belong to the vegetable king- 

 dom. But in fact the name Infusoria is now applied by the best 

 authorities only to the highest division of Protozoa; and it is highly 

 convenient that this limitation should be observed. The work then 

 treats of microscopic animals and vegetables,— but among the former 

 it entirely omits Sponges and Polycystina, not to mention smaller 

 groups ; and it neither is nor professes to be an account of the lowest 

 vegetable structures generally, but only treats incidentally of some 

 which have been recently supposed to be animal. The work, then, 



