ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 1095 



partially remedy this he tried Eau de Javelle diluted with four times 

 its volume of water. The animals, hardened in Frenzel's or in List's 

 sublimate and picric acid mixtures or in 90 per cent, alcohol, were 

 left in the fluid for 18 to 21 hours. After being well washed they 

 were gradually hardened in alcohol and then imbedded in paraffin. 



Thus diluted Eau de Javelle permits good staining (alum carmine 

 and picrocarmine) even though five or six days may be required. 

 Secondly, the chitin loses its great brittleness, and good sections 

 are obtained. Thirdly, no alteration of the delicate structures was 

 observable. In order to render the animals transparent for 

 examiuation of the parts about the gullet, the author boiled them 

 in the undiluted fluid, but prefers a 10 per cent, potash solution on 

 account of its more speedy action. 



Eau de Javelle as a test for very minute Starch particles.* — 

 Dr. E. Heinricher, in commenting on the resisting power of starch to 

 Eau de Javelle, remarks that after acting for four days on the leaves of 

 Argemone grandijlora no starch granules were to be found in the cells 

 but that the iodine reaction gave evidence of a starchy paste therein. 

 So, too, leaves of Crambe cordifolia showed starch afte,r 24 hours' 

 immersion in Eau de Javelle though all the rest of the cell-constitu- 

 ents were destroyed. If, however, a glass stoppered bottle instead 

 of open vessels be used and put in a dark place, the action ensues 

 more quickly. Hence from destroying the plasmatic substances 

 and the relatively late solution of the starch Eau de Javelle may be 

 considered suitable for the demonstration of the smallest quantities of 

 starch, and the author finds this test, when combined with iodine, to be 

 more sensitive than that recently advocated by Schimper who advised 

 a combination of chloral and iodine. 



Resins used for Microscopical Purposes.! — 1. Shellac. — Dr. O. 

 N. Witt remarks that the conflicting views on the value of shellac 

 are due probably to impurities, although the purest shellac is a com- 

 plex mixture of different substances, aud he endeavours to show that 

 only a part of these constituents possess properties useful to the 

 microscopist. 



There are two varieties of shellac, the raw or unbleached, 

 and the bleached. The latter is obtained by removing the colour- 

 ing matter from the former variety by means of Eau do Javelle 

 and hydrochloric acid. Apart from the colouring matter the two 

 kinds are alike, being composed of three constituents, wax, resin, and 

 a body chemically allied to fat, being the glyceride of an acid, for on 

 dry distillation it produces acrolein. It is the resin, however, which 

 gives shellac its microscopical value, and this the auther obtained by 

 first removing the wax by acting on powdered bleached shellac with 

 petroleuni-benzin in the cold. When some of the solution, allowed 

 to evaporate in a watchglass, does not leave a residue of wax the 

 treatment is suspended. The powder, spread on filter-paper, is dried 

 in the air, and the resin obtained therefrom by dissolving it in a large 

 quantity of alcohol. 



* Zeitschr. f. Wiss. Mikr., iii. (1886) pp, 213-5. f Ibid., pp. 19G-206. 



