Book N'otices. 8i 



Microscopical Research. — From " Scientific Opinion, "June, 1869. 



Notes on Century III. of the "Species Typic.e Diatomace- 

 ARUM." — Prof. H. L. Smith. 



A Microscopical Cabinet. — A description of a cabinet devised by 

 Dr. Mouser and exhibited before the San Francisco Microscopical 

 Society. 



Balsam Mounts. — Dr. F. M. HamHn. — Recommending a ring of 

 gold size around balsam mounts to protect them. 



Collection of Canada Balsam. — From the Transactions Am. 

 Pharmaceutical Association. 



BOOK NOTICES. 



Microscopic Organisms in Cociiituate Water. By Robert White, 

 Jr., M. D. Reprinted from The Boston Medical and Surgical Journal. River- 

 side Press, Cambridge, 1878. This is a neat pamphlet of ten pages, and a plate 

 fairly illustrating the more common forms of plant and animal life found in drink- 

 ing water. After describing his method of examination, the author recounts 

 briefly the characters of the various genera represented, touching upon their 

 habitat and methods of growth and multiplication. The living forms in the 

 Cochiluate water he considers to be harmless, and the only objectionable feature of 

 the water lies in the amount of "organic matter" which it contains, which 

 "indicates the necessity of carefully protecting it from all sources of pollution."' 



ISTHMIA Nervosa. A study of its modes of growth and reproduction. By 

 J. D, Cox, A. M., LL. D. Reprinted from the American yoiirnal 0/ Micro- 

 scopy. Many of our readers have already seen the contents of this pamphlet. 

 It embraces the results of a careful study of the silicious frustules as they were 

 found upon sea-weed, and shows well that there is much to be learned about 

 methods of growth, and even multiplication, by the examination of dead speci- 

 mens. Commencing with a short description of the appearance of the frustule, 

 a general account of the phenomena of subdivision follows, after which the 

 so-called "hoops "are considered. While agreeing with Dr. Wallich as to the 

 presence of two or more hoops, sliding one over the other like telescope tubes, 

 Mr. Cox differs from him as to their manner of growth. According to Mr. Cox 

 the hoops are made up of a membrane upon, or in which, the silex is deposited 

 after the manner of plant growth. The outer hoop frequently shows one or more 

 sutures at which the edges of the two parts are slightly separated so as to show 

 the inner tube, and there is always a line of suture at each end of the hoop. 

 The hoop and valve never sever their connection during life. When the frustule 

 has reached the proper stage, subdivision begins within, and as the young cells 

 grow, they force the old valves apart, and thus cause the telescope tubes to slide 

 over each other. 



The most important part of Mr. Cox's pamphlet relates to his observations on 

 the sporangial frustule, and they will no doubt require verification from the study 

 of living forms before receiving general support from diatomists. He considers 

 that his observations prove that the sporangial frustules propagate by division in 



