172 



THE AMERICAN MONTHLY 



[September, 



i 



J 



EDITORIAL. 



Microscopical Section of the A. 

 A. A. S. — We are informed, by the 

 Rev. A. B. Hervey, that at the Cincin- 

 nati meeting of the A. A. A. S., the 

 microscopical sub-section was chang- 

 ed into a full " Section of Histology 

 and Microscopy." Hereafter, the 

 Chairman will be a Vice-President of 

 the Association, and the section will 

 be represented in the standing com- 

 mittee by the Chairman, Secretary 

 and one Fellow. 



Prof. A. H. Tuttle, of Columbus, 

 was elected Chairman for the next 

 meeting, which will be held at Mon- 

 treal, and Mr. Robert Brown, Jr., was 

 made Secretary. Next month, we shall 

 print the article read at the meeting 

 by the Hon. J. D. Cox, on the conju- 

 gation of Actinophrys sol, which is very 

 interesting. 



Exchanges. — It is not usual that 

 we know just what kind of material 

 is offered for exchange on our last 

 page, and we cannot, therefore, be 

 held in any wise responsible if those 

 who make exchanges do not always 

 receive objects equal to those they 

 send out. Some disappointments 

 will necessarily arise from this source, 

 but we have heard only a very few 

 complaints thus far. Miss M. A. 

 Booth offers some most excellent 

 material in the form of diatoms in 

 situ, specimens of which we have 

 seen, and our readers would do well 

 to obtain some of her collections for 

 mounting. 



Croton Water. — In addition to 

 the list of algae found in Croton wa- 

 ter, printed last month, a number of 

 other species have since been deter- 

 mined, and still others are found 

 which we have as yet been unable to 

 classify. The life-history of most of 

 the so-called unicellular algae is not 

 known, but it is supposed that these 

 simple forms of vegetal life are, in 

 many cases, the spores, or develop- 



mental stages, of higher algae. Never- 

 theless, specific names have been 

 given to them, and they are not 

 without value in the present state of 

 our knowledge. But many of the 

 forms are so indefinite that it is al- 

 most impossible to identify them 

 with any one described species. 

 Hence, there is a considerable num- 

 ber of minute forms to be found in 

 Croton water, to which we have not 

 ventured to give names. As an ex- 

 ample of what we have stated, we 

 may refer to the plant named in our 

 list Palmodactylon varium. There was 

 certainly found a plant which, in all 

 respects, agreed with Rabenhorst's 

 description and figure of that species. 

 However, later examinations of the 

 sediment have almost convinced us 

 that the plant we have thus named, 

 and which Mr. Wolle regarded as 

 correctly named, is merely a stage 

 in the life of Coelosphcerium dubium, 

 the gelatinous spherical families of 

 which show a tendency to break up 

 in this way. However, that they ac- 

 tually do break up in this way is not 

 yet positively demonstrated, but we 

 have pretty strong evidence, that 

 they do. C. dubium is now exceed- 

 ingly abundant in the Croton water, 

 but the Anabaenas have almost dis- 

 appeared. In addition to the forms 

 named in our preceding list we have 

 found the following species : — 



Anabcena bullosa. 



Anabcena . 



Scendesmus acutus. 



Staurastrum megacanthum. 



Spirogyra Weberi {?). 



Objectives. — Dr. Carpenter, in the 

 last edition of his book, has written 

 some plain words about the relative 

 qualities of objectives. Without in- 

 tending to reopen the discussion of 

 the intrisic merits of high and low- 

 angled objectives, about which there 

 is no longer any occasion for contro- 

 versy, since the matter is capable of 

 accurate mathematical demonstration, 

 we still believe that a little whole- 



