112 



THE AMERICAN MONTHLY 



[June, 



rectly from the oil, but in doing so as 

 much of the latter as possible should 

 be removed with bibulous paper. 



{To be contmticdJ) 



EDITORIAL. 



Publisher's Notices.— All communications, re- 

 mittances, exchanges, etc., should be addressed to the 

 Editor, P. O. Box 630, Washington, D. C. 



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Subscription-price before April ist,$i per year, in 

 advance. All subscriptions after this month begin 

 with the January number. After April 1st the sub- 

 scription-price will be $1.50. 



The regular receipt of the Journal will be an ac- 

 knowledgment of payment. 



— The delay in publishing the 

 JouRNAi- this month has been caused 

 by the absence of the editor, who was 

 called away early in the inonth by 

 the death of his father. Proofs did 

 not reach him as expected, and could 

 not be read until the 15th instant. 



Photographs Showing the 

 Structure of Diatom-Shells. — 

 We have i-eceived thirteen very ex- 

 cellent photomicrographs made by 

 the Hon. J. D. Cox to illustrate some 

 points embodied in his articles on the 

 structure of the diatom-shell, the last 

 of v^^hich is published this month. 

 These photographs are from what he 

 designates the ' broken-shell series.' 

 All were taken with a y^ of William 

 Wales. They seem to fully sustain 

 the arguments of the author of the 

 articles, several of them in a very 

 striking manner. Thus, in two of 

 them (Nos. 21 and 22) the dotted 

 film of Coscinodiscus oculis-iridis 

 projects beyond the hexagonal walls 

 at the line of fracture, and the broken 

 edge of the film can be seen. On two 

 other cards (26 and 27) we find the 

 film vs^ith its dots, in fragments of Tri- 

 ceratium and Heliofelta respective- 

 ly, the latter being especially striking, 

 showing the dotted film extending 

 fully an inch from the hexagonal 

 structure at the line of fracture. The 

 series includes fractured shells of other 

 genera, Odontodis cus^ Epithemia^ 



and several species of Navicular all 

 of which tend to demonsti'ate more 

 or less clearly the imperforate nature 

 of the diatom-shell. 



We are not aware that photography 

 has been hitherto employed to sustain 

 facts of observation of this nature. In 

 this case it proves to be of great value, 

 since it shows clearly what has been 

 seen, and enables others to verify state- 

 ments which otherwise might be un- 

 satisfactory or unconvincing to those 

 holding other views concerning the 

 structure of the shells. We have now 

 evidence that must receive careful 

 consideration, and which can only be 

 overthrown by evidence of the same 

 kind, which demonstrates in the same 

 clear manner any errors or misinter- 

 pretations of the work before us, 

 which is now ofi'ered to the micro- 

 scopical world for critical examina- 

 tion. The photographs were made 

 with magnification ranging from 650 

 up to 1600, and are very clear and 

 sharp. 



Since writing the above, six more 

 photographs have come to hand, two 

 of which deserve special mention. 

 A broken frustule of Navicula gran- 

 ulata^ Breb., mounted dry, shows 

 the broken edge with extreme clear- 

 ness, but the most inteix'sting, and 

 perhaps the most valuable photograph 

 of all in throwing light upon the .sub- 

 ject, is one taken from a Pleurosigma 

 angulatum^ W. Sm., of Calvert 

 county, Md., deposit, mounted in 

 balsam by Mr. Peticolas. In this 

 the fractured edge shows the break 

 through the dots, and the indented 

 margin, with remarkable clearness, 

 .considering the fineness of the mark- 

 ings. 



o 



Killing and Preserving Deli- 

 cate Organisms. — We have already 

 several times mentioned the use of 

 perchloride of iron for killing minute 

 animals for mounting, and it seems 

 to be coming into favor. In the 

 Journ. R. Mic7'. Soc. we find a fur- 

 ther notice of experiments by H. FoJ, 

 who has used the reagent very sue- 



