ZOOLOGY AND BOTANY, MICEOSCOPY, ETC. 283 



teristic property of traclieids is the very early and strong develop- 

 ment of lignification in their cell-walls. In the walls and disks of 

 sieve-plates, on the contrary, indol produces not the least reaction. 



Protoplasm acquires a slight rose-colour with indol and sulphuric 

 acid, but no differentiation of the nucleus is observable ; the contents 

 of the stinging hairs of the nettle assume throughout a red colour. 

 No effect is produced on the contents of resin-passages. 



The author concludes that the red colour imparted by indol and 

 sulphuric acid is an unfailing test for the lignification of the cell- 

 wall. 



English's Method of Preserving Hymenomycetes and Wild 

 Flowers.* — When we mention that the price of this book is 7s, 6d., 

 and that each of the two sections only contains as much matter as two 

 columns of the Times, it will be obvious that it cannot be abstracted 

 without seriously interfering with its proprietor's expected profits. 

 We therefore confine ourselves to generalities. 



For Fungi, a double preservative compound is used, formed of 

 British farina, methylated spirit and corrosive sublimate, osalic acid and 

 sulphur. There is also an " adjunct to the process," formed of plaster 

 of Paris and sulphur, for imbedding the specimens after the preserva- 

 tive has been applied. The final process consists of varnishing. 

 Waxing and colouring can also be adopted if desired, for which 

 directions are given. 



The process for flowers (which has only been tried for two years) 

 is to imbed them in plaster and lime as an absorbent, and gradually 

 heat them up to 100° F. After dusting, they are varnished with 

 similar varnish to that used for Fungi. 



Mounting Salicine Crystals.! — Dr. D. H. Briggs recommends 

 the following process : — 



Clean the slide perfectly with ammonia, then rinse with hot water 

 and cleanse with ammonia again. 



Add to the salicine from one-tenth to one-twentieth its weight of 

 pulverized gum arable. Make a nearly saturated solution of the 

 salicine and gum in distilled water, or in ice-water heated to the 

 boiling point, and carefully filter the solution. Heat the solution to 

 100° C. in the beaker, and pour the hot solution upon a still hotter (sic) 

 slide, and drain off. Only a hot solution will give bright colours. 



Hold the slide, and watch for disks of crystals. As soon as these 

 appear, place the slide on a cold iron block. 



A rim is put on the crystals by another heating over the lamp and 

 another cooling on the iron. Without delay heat a drop of Canada 

 balsam on a circular cover-glass, and apply the cover to the crystals, 

 and fasten with white zinc cement on a turntable. 



The process described, if followed with care, will yield most 



* English, J. L., 'A Manual for the Preservation of the Larger Fungi (Hymeno- 

 mycetes) in their natural condition, by a new and approved Method ; also a new 

 Process for the Preservation of Wild Flowers.' viii. and 41 pp. 8vo. Epping 

 1882 



t" Amer. Mon. Micr. Jouru., ii. (1881) pp. 227-8. 



