METHODS .FOB INVEETEBRATES. 455 



part and sea water 5 parts, and brings into alcoliol of 70 per 

 cent. 



Stappees [La Cellule, xxv, 1909, p. 356) fixes Sympoda in 

 GtIlsgn's copper formol, § 115, or in Hoknell's mixture of 100 

 parts of 5 per cent, formol with 40 of alcoliol ; and for 

 softening the chitin puts for 12 to 36 hours into 3 per 

 cent, solution of sublimate with 5 per cent, of nitric acid. 



Nettovitch [Arb. z. Inst. Wien, xiii, 1900, p. 3) Axes Argulus 

 with liquid of Tellyesniczky, § 52, warmed to 50° 0. 



For FiscHEi/s intra-vitam stain of Cladocera with alizarin 

 etc., see § 208. 



867. Tracheata.— Kenton [Tufts Goll. Stud., No. 4, 1896, 

 p. 80) fixes Pauropoda in Carnoy's acetic alcohol and chloro- 

 form, § 85, cuts them in two for staining, etc., and imbeds in 

 celloidin followed by paraffin. 



Hennings {Zeit. wiss. Mile., xvii, 1900, p. 311) takes — 

 Nitric acid 16 parts, chromic acid of 0'5 per cent. 16 parts, 

 sublimate saturated in 60 per cent, alcohol 24 parts, picric 

 acid saturated in water 12, and absolute alcohol 42, fixes for 

 twelve to twenty-four hoiii's, 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 (^8iiz. Natiirw. 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(.ZooZ. J.7iJ!., xxxii, 1907, p. 318) takes for larvaa 

 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. 



Ndttall, Coopee and Robinson (^Parasitology, 1908, i, 

 p. 163), fix for a few minutes in hot picrosulphuric acid. 



868. Methods for Clearing and Softening Chitin. — The methods 

 of Looss have been described § 553, those of Hennings and 

 Hamann last §, 



