160 THE AMERICAN MONTHLY [July, 



fragments of valves with their areola2 filled in with silver 

 sulphide, mercurous sulphide, or platinum : one to ISIr. 

 Andrew Pringle, and one to Mr. Thomas Comber, both 

 of England, for fine diatom photographs; and one to F. Thevoz 

 & Co., of Geneva, for a large and excellent variety of " photo- 

 types," impressions suitable for book illustrations, from photo- 

 micrographs of diatoms, infusoria, microbes, and natural-history 

 objects generally. 



A novel and remarkable series of photomicrographic transparen- 

 cies suitable for the magic lantern was shown by Antoine Lumiere 

 & Son, of Lyons, France. The gelatin bromide of silver trans- 

 parencies were cleared and stained, by some process claimed as 

 original, so that the color of the object as seen in the field of the 

 microscope was exactly reproduced. Thus desmids, for instance, 

 were stained a natural green, while microbes, animal tissues, or 

 plant sections, which are usually stained for the microscope, were 

 colored to correspond. The transparencies when held up to the 

 light, or displayed by hanging in the windows, represented vividly 

 the field of view in the microscope itself, and in the magic lantern 

 or with a sufficientlv low power of the projection microscope 

 they produced that effect well upon the wall. At a lecture in the 

 amphitheatre many of these views, including a series representing 

 the embryology of the chick, were projected upon the screen with 

 good efiect. • 



Several collections that were not remarkable as photographs 

 were interesting, and perhaps even more valuable as demonstra- 

 tions of natural history or of economic science, and as examples 

 of thorough and useful scientific work. Such was the comparative 

 study of the structure of oih' seeds by Director Fred. D'Hont and 

 Mr. F. Moreau, of the communal laboratory at Courtrai, Belgium, 

 illustrated with six large frames full of photographs (x icx)), and 

 with a side case displaying a set, complete in every detail, of the 

 few simple instruments, reagents, etc., used in the investigation. 

 A somewhat similar study of the comparative histology of the 

 seeds of the cabbage, mustard, flax, and other plants of com- 

 mercial importance was shown by Director Paul Claes and Mr. 

 Emile Thyes of the state agricultural laboratory at Louvain. Mr. 

 Ed. Anseel, of Antwerp, likewise exhibited a set of three dozen 

 views, adequately magnified, demonstrating the character of the 

 hairs of different animals. It would be difficult to commend too 

 highly the educational and economical value of this class of 

 work. 



Bacteriology. 



The two principal exhibits in this class consisted of extensive 

 selections from the vast variety of apparatus made by E. Adnet 

 and by V. Wiesnegg, both of Paris. The sterilizing and incubat- 

 ing ovens, baths, furnaces, and lamps, stills, filters and refrigera- 

 tors, and the large variet}- of associated apparatus constituted ex- 



