90 The Microscope. 



Carbolic acid for dehydrating. — In insect work I have 

 found carbolic acid a very great help. In addition to the tur- 

 pentine solution mentioned in the October number of The Mic- 

 roscope, I have a solution made by dissolving the pure detached- 

 crystals of carbolic acid in just enough strong alcohol (absolute 

 preferred) to liquefy the acid, with aid of a gentle heat. This 

 solution has great affinity for water and will readily extract it 

 from any object, hence its utility in clearing insect specimens. 

 The skin of the ordinary cricket containining the spiracles, taken 

 from a fresh specimen, washed in water and then placed in this 

 solution, will be entirely dehydrated in less than five minutes ; 

 now by placing it in the turpentine oil for a few minutes, to free 

 it from the alcohol, it will be ready to mount in balsam. It is^ 

 possible in this way to mount a thin object in less than fifteen 

 minutes from the time you dissect it. This method is especially 

 applicable to such objects as the skin and wings of insects, giz- 

 zard of cricket, etc. In addition to the saving of time, as the 

 object is handled but once it will be much more likely to remain 

 in a whole condition, especially in the case of a delicate struc- 

 ture, than by the old potash process. One word of caution in 

 using this strong solution ; it is a poison, and is besides very 

 caustic and must be kept from the hands and clothes. — E. W. 

 Sharp. Ph. G. 



PVBLICATIONS 



The Diatomace.e of North America. — Kev Francis Wolle. 

 Illustrated with 2,300 figures. 8vo. Price $6.00. Bethlehem, Pa. : 

 The author. — Mr Wolle's " Desmids," " Fresh water Algse " and 

 this volume together form a complete treatise on these three great 

 groups of aquatic plants as found in this cpuntry. The mono- 

 graphs form a monument to the author's learning, skill and 

 indomitable energy. To have looked forward to the preparation 

 of this volume on the Diatomaceaj must in itself have been a 

 formidable prospect. The literature of the subject is perhaps 



