506 METHODS FOR INVERTEBRATES. 



hours, and washes out with iodine alcohol. He says that this 

 mixture not only fixes, but softens chitin enough to allow of paraffin 

 sections being made through hard parts. 



HAMANN (Sitz. Naturw. Freunde Berlin, 1897, p. 2) fixes small 

 Tracheata in 10 per cent, formol and finds the chitin sufficiently 

 soft for sections to be made. 



VAN LEEUWEN (Zool. Anz., xxxii, 1907, p. 318) takes for larvae 

 of Hexapoda 12 parts of 1 per cent, solution of picric acid in absolute 

 alcohol, 2 of chloroform, 2 of formol, and 1 of acetic acid. 



HOLLANDE (Arch. d'Anat. mic., xiii, 1911, p. 171) takes 12 parts 

 of saturated solution of picric acid in formol of 40 per cent., 54 of 

 absolute alcohol, 3 of benzene, and 1 of nitric acid, and finds that 

 this fixes quickly enough not to make chitin too hard. 



NUTTALL, COOPER and ROBINSON (Para&itology, 1908, i, p. 163) 

 fix for a few minutes in hot picrosulphuric acid. 



945. Methods for Clearing and Softening Chitin. The methods 

 of Looss have been described 545, those of HENNINGS and HAMANN 

 last . 



LIST (Zeit. wiss. MiL, 1886, p. 212) treats Coccidse (after harden- 

 ing) for eighteen to twenty-four hours with eau de Javelle, diluted 

 with 4 volumes of water. After washing out they may be embedded 

 in paraffin, and good sections obtained. 



BALING (Dissert. Marburg., 1906, p. 11) boils larvae of Tenebrio 

 for some minutes in eau de Labarraque, the heat serving to fix the 

 soft parts, which in successful cases are well preserved. Wash out 

 with warm water, then alcohol. 



SAZEPIN'S method for antennae of Chilognatha (Mem. Acad. Imp. 

 St. Petersb., xxxii, 1884, pp. 11, 12) consists in steeping antennae 

 (that have been dehydrated with alcohol) for twenty-four hours ih 

 chloroform containing a drop of fuming nitric acid (shake occasion- 

 ally). 



BETHE (Zool. Jahrb., viii, 1895, p. 544) puts telsons of Mysis 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 somewhat breaks down the structure of the 

 otolith, so that good sections through it are occasionally obtained. 



Similarly HERBST, Arch. Entwickelungsmech, ix, 1899, p. 291. 



See also the depigmentation processes, 567 to 576. 



945 A. Double Embedding of Insects. Dissolve 1 -5 grs. desiccated 

 celloidin chips in 50 c.c. clove oil, or, better, add the celloidin in 



