Notes and Memoranda. 399 



descriptions of new specimens from Macloc and from Long Lake 

 and Wentworth, Dr. Dawson discussed* the objections of Prof. 

 King and Dr. Rowney to the view of the organic nature of Eozoon, 

 and stated that those gentlemen had failed to distinguish between 

 the organic and the crystalline forms, as was especially illustrated 

 by their regarding the veins of crysotile as identical with the tubu- 

 lated cell-wall of Eozoon. 



ROYAL MICROSCOPICAL SOCIETY.— May 8. 

 James Glaisher, Esq., F.R.S., President, in the Chair. 



The Rev. J. B. Reade, F.R.S., read a paper on a remarkable 

 dichroic liquid obtained from a pond. The water was tinged with 

 a colouring matter which appeared red by reflected, and violet by 

 transmitted light. The peculiarity seemed to result from the action 

 of growing organisms npon soluble albumen, and Mr. Reade 

 exhibited a similar fluid artificially formed. Mr. Browning explained 

 the character of its spectrum, which was very remarkable, the 

 principal characteristics being two cloudy absorption bands, one 

 in the orange and another in the green. 



Two new lamps were described by Ellis G. Lobb, Esq., one a 

 small camphine lamp, patented by Young, and the other a cheap 

 and convenient travelling lamp, devised by Mr. Piper ; both were 

 considered very handy. Dr. Lionel Beule read a very interesting 

 paper on " Nutrition considered from a Microscopical Point m 

 View," in which he developed the hypothesis that all matter capable 

 of growth by nutrition originates by descent from similar matter. 

 He also showed that the serum of the blood, and not the globules, 

 was its nutritive portion. 



NOTES AND MEMORANDA. 



The Stability of Gun Cotton.— Proc. Hoy. Soc, No. 92, contains a paper 

 on this subject by Mr. F. A. Abel, F.R.S., in which he states that if gun-cotton 

 is prepared in strict accordance with Von Lenk's system, it will resist to a remark- 

 able degree the destructive effects of prolonged exposure to temperatures even 

 approaching 100° C. Ordinary gun-cotton contains small quantities of nitro- 

 genous impurities, Avhich decompose and give rise to a free acid when exposed to 

 heat. One per cent, of sodic carbonate neutralizes this acid, and is sufficient to 

 prevent serious change. Water acts as a most perfect protection to gun-cotton 

 (except when it is exposed for long periods to sunlight), even under extremely 

 severe conditions of exposure to heat. It is not necessary that the gun-cotton 

 should be wet, a slight dampness being sufficient. 



Mimetic Butterflies.— Mr. Wallace has been exhibiting at 76£, West- 

 bourne Grove, a very interesting series of objects from the Indian archipelago. 

 Amongst them is a case with a label affixed, stating that it contains fourteen but- 

 terflies. The visitor is completely puzzled, seeing only twigs with dead leaves 

 upon them. On closer examination, it appears that each seeming dead leaf is a 

 butterfly, with wings folded, and perched on the twig so as exactly to resemble 

 the insertion of a leaf. To make the imitation more complete, the undersides of 

 the wings, which alone are visible, are speckled with dull colours resembling 

 patches of microscopic fungi. 



