NOTES AND MEMORANDA. 181 



to the member whose name stands first on the list, who should keep it 

 three evenings only, and then send it to the next name, and he to the 

 following one, the last on the list returning it to the secretary, by 

 whom it is sent to the next circuit, and so on. Each box is accom- 

 panied by one or more MS. books, in which the members are requested 

 to make remarks on the slides. 



From the Fifth Annual Eeport it appears that the Society 

 numbers 140, including six ladies who are now eligible for 

 membership. In the Address of the President, Mr. Tutfen West, 

 F.Z.S., F.R.M.S., the safe transit of slides and the best form of postal 

 box were among the principal topics dealt with. 



A special feature is the requirement of the Society that each 

 member on admission shall send his carte de visite to the secretary. 

 They are then grouped (sixty or seventy together) and reproduced in 

 permanent photography by the Woodbury process, and supplied to the 

 members. 



It is intended to circulate a separate series of histological and 

 pathological slides amongst the medical members. 



Life-History of the Diatomacese. — M. Paul Petit, whose obser- 

 vations on the revivification of diatoms will be remembered,* con- 

 tributes to the French Botanical Society some further remarks f on 

 diatoms. That so little is known of their life-history is, he thinks, 

 the fault of the " diatomophiles," who have preferred to create new 

 species or to count the number of striae on the valves rather than to 

 devote themselves to physiological researches. The impossibility (as 

 M. Petit considers) of growing diatoms in an aquarium, as can be 

 done with others of the lower cryptogamia, necessitates the noting of 

 all the phenomena which are met with in nature. We shall thus, 

 sooner or later, understand the ensemble of the phases through which 

 diatoms pass during their existence. 



He accordingly describes the following observations made by 

 Professor Brun, of Geneva : — 



On the 5th-7th of January, 1878, M. Brun gathered some mud 

 which covered the rocks at the lower part of the Mer de Glace at 

 Chamounix (1150 metres). Deep snow covered the valley and the 

 mountains, the thermometer standing at 18° (C.) below zero ; but as 

 the ice melts in contact with the rock (even in winter), the rock 

 is thus moistened by water at zero. The mud contained a great 

 quantity of diatoms and some desmids, all in a perfect state of 

 vegetation. Lower down in the valley a small piece of water at 0^, 

 covered with ice, was overrun with Melosira varians in full vegetation. 



Some specimens from the mud of the Mer de Glace were sent to 

 M. Petit by post, and he found that the endochrome of all was in a 

 perfect state, and that the Naviciilce exhibited their movement. 



The second observation was made in the Valais, on the Bella Tola, 

 at 2600 metres, on the 19th and 20th January. The temperature was 

 9° below zero, and the snow was lying thick. Here also M. Brun 

 found that the algae and diatoms were living wherever the snow 

 melted in contact with the warmer rock, and where the light reached. 



* This Journal, vol. i. p. 26. f ' BrtTbissonia,' vol. i. (1878) p. 81. 



