456 CHAPTEE XXXVI. 



List {Zeit. iviss. Mile, 188Q, p. 212) treats Coocidas (after 

 hardening) for eighteen to twenty-four hours with ean de 

 Javelle, diluted with four volumes of water. After washing 

 out they may be imbedded in paraffin, and good sections 

 obtained. 



Baling {Dissert. Marburg. 1906, p. 11) boils larvae of 

 Tenebrlo for some minutes in eau de Laharraque, the heat 

 serving to fix the soft parts, which in succesisful cases are 

 well preserved. Wash out with warm water, then alcohol. 



Sazepin's method for antennse of Chilognatha (Mem. Acad. 

 Imp. St. Pi'tersb., xxxii, 1884, pp. 11, 12) consists in steep- 

 ing antennas (that have been dehydrated with alcohol) for 

 twenty- four hours in chloroform containing a drop of 

 fuming nitric acid (shako occasionally). 



Bethe {Zool. Jahrb., viii, 1895, p. 544) puts t(dsons of 

 Mjj.ns for eight to fourteen days into 40 per cent, alcohol, 

 to which nitric acid is gradually added, so that by the end 

 of that time they have been brought into alcohol containing 

 20 per cent, of the acid. This softens the chitin, and some- 

 what breaks down the structure of the otolith, so that good 

 sections through it are occasionally obtained. 



Similarly Heebst, Arch. Enttrichelungsmech ix, 1899 

 p. 291. 



See also the depigmentation processes, §§ 57.5 — 584. 



869. Test for Chitin (Zander, Pfliiger's Arch., Ixvi, 1897, p. -545).— 

 Treat for a short time with a drop of freshly prepared solution of iodine 

 in iodide of potassium and add a drop of concentrated chloride of zinc. 

 This is then removed with water as far as possible, and the violet 

 reaction is obtained. 



See also Wester, Zool. Jahrh., Ahlh. Sijst., xxviii, 1910, p. 531. 



870. Bbthe's Stain for Chitin {loc. cit., § 868).— Sections are put 

 for three or four minutes into a freshly prepared 10 per cent, solution of 

 anilin hydrochloride, to which has been added one drop of hydrochloric 

 acid for every 10 c.c. They are then rinsed in water, and the slide is 

 put with the sections downwards into 10 per cent, solution of bichro- 

 mate of potash. The stain is at first green, but becomes blue in tap 

 water or alcohol containing ammonia. 



Mayer simply uses a solution of pyrogallol in alcohol or glycerin ; 

 and HOPMANN {Zeit. ww.',-. Zool., Ixxxix, 1908, p. 684) puts for a day or 

 more into j-aw pyroligneous acid. 



871. Tracheae may be studied by the Golgi bichromate and 



