NOTES. 227 



known to exist at present. M.M. Eeynault and Bertrand throw 

 out the suggestion that possibly there may be only one species of 

 bacterium which is polymorphic. — Brit. Med. Journal. 



Impressions in Sulphur. — M. Lepirre, a French artist, states 

 that in demonstrating that sulphur melted at about 150^ can be 

 cooled in paper, he happened to use a lithographic card, of which 

 the edges were turned up. Upon taking away the card, it was dis- 

 covered that the lithographed characters were clearly and distinctly 

 impressed upon the cooled surface of the sulphur, remaining thus 

 after hard friction and washing. By repeated experiments in this 

 direction, he has succeeded in obtaining results of a very satisfac- 

 tory character, removing the paper each time by a mere washing 

 and rubbing process. It is found, in fact, that sulphur will receive 

 impressions from, and reproduce in a faithful manner, characters 

 or designs in ordinary graphite crayon, coloured crayon, writing 

 ink, typographical inks, china ink, hthographic inks — whether 

 coloured or uncoloured varieties — and others. He also states 

 that it will reproduce with remarkable exactitude maps. 



According to Nature^ in a paper read at the Botanical Congress 

 at Genoa last year (1893), Professor Saccards calculates the num- 

 ber of species of plants at present known as 173,706, distributed 

 as follows: — Flowering plants, 105,231; ferns, 2,819; other vas- 

 cular cryptogams, 565 ; mosses, 4,609 ; hepaticae, 3,041 ; lichens, 

 5,600; fungi, 39,603; algae, 12,178. Professor Saccards thinks it 

 probable that the total number of existing species of fungi may 

 amount to 250,000, and that of all other species of plants to 

 135,000. 



Adherence of Metals to Glass, etc. — C. Margot finds that 

 aluminium, magnesium, cadmium, and zinc possess the property of 

 marking glass and other substances containing much silica, in such 

 a way that neither rubbing nor ordinary washing will remove the 

 marks. Taking advantage of this curious property, he constructed 

 pencils and wheels of aluminium, by means of which designs can 

 be drawn upon glass, and it is understood that mirrors, etc., now 

 being sold in London, which reveal figures and various devices 

 when breathed upon, are prepared in this way. The effect is much 

 the same as when sketches are drawn on glass with French chalk, 

 but more permanent. — Arch. Soc. Phys. et Nat. de Geneve and 

 /ourn. de Pharni. (6), I., 263. 



