304 CHAPTER XXV. 



solution of Kleinenberg, and are then brought through 

 alcohol of gradually increasing strength. 



CHILD (quoted from SUMNER ; Mem. New York Acad. Sci., 

 ii, WOO, p. 78) fixes for about a minute in sublimate with 10 

 per cent, of acetic acid, and brings into formalin of 10 per 

 cent., which is said to give a good fixation of the embryo 

 without the yolk becoming hard. 



610. KOLLMANN'S Fixative (KOLLMANN, Arch. Anat. Phys., 1885, 

 p. 296). 



Bichromic of potash . . . . .5 per 100. 



Chromic acid . . . . . . 2 ,, 



Concentrated nitric acid . . . . 2 ,, 



For ova of Teleostea. Fix for twelve hours, wash with water for 



twelve hours, then remove the chorion, and put the ova into 70 per cent. 



alcohol. 



611. RABL'S Method see 587 ; for KOWALEWSKY'S see Zeit. wiss. 

 Zool, xliii, 1886, p. 434, or Third Edition. 



612. Salmonidse. HENNEGUY'S methods have been given, 

 609. 



KOPSCH (Arch. mik. Anat., li, 1897, p. 184), on the sug- 

 gestion of VIRCHOW, fixes embryos for five or ten minutes 

 in a mixture of 1 part of chromic acid to 50 of glacial acetic 

 acid and 450 of water, then removes into chromic acid of 

 1 : 500, and as soon as may be removes the capsule and yolk 

 under salt solution, and completes the hardening in the 

 chromic acid or the saturated sublimate solution. 



Similarly, BEHRENS (Anat. Hefte, x, 1898, p. 233). He 

 opens the ova in the salt solution from the antipolar side, 

 and frees the embryo from the yolk that remains by blowing 

 the latter away with a fine-pointed glass tube. 



Similarly also SOBOTTA (ibid., 1902, p. 579). 



GUDGER (Proc. U.S. Nation. Mns., xxix, 1906, p. 448) 

 fixes blastoderms in fresh liquid of Perenyi, which does not 

 make the yolk too hard ; later stages in WORCESTER'S liquid 

 (9 parts of saturated solution of sublimate in formol of 10 

 per cent, and 1 part of acetic acid), for half an hour to an 

 hour, and brings gradually into alcohol of 70 per cent. 



BOUIN (C. R. Soc. Biol., Iv, 1903, p. 1691) fixes for 36 to 

 48 hours in picro-formol. 



RABL-RUCKHARD'S Method (Arch. Anat. Entw., 1882, p. 118). Fix in 

 10 per cent, nitric acid for fifteen minutes. Remove the membranes to 



