356 CHAPTER XXVI. 



643. Trematoda. COE (Zool. Jalirl., Abth. Morpli., ix, 1896, 

 pp. 563, 566) fixes the Miracidia of Distomum for general 

 purposes with the usual fixatives ; but for the special study 

 of the excretory system he kills them with osmic acid, rinses 

 with distilled water, and puts them for a couple of days into 

 per cent, solution of silver nitrate. 



644. Nematoda. BOVERI (Jena. Zeit., xxi, 1887, p. 423) 

 fixes the ova of Ascaris in his picro-acetic acid (after which 

 treatment I should say you may easily see anything 1 you like 

 to imagine in them). 



ZUB STKASSEN (Arch. Entivickelungsmech., iii, 1896, p. 29) 

 fixes them for twenty- four hours in a mixture of 4 parts 

 96 per cent, alcohol and 1 part acetic acid (much too long, 

 I should say), b ring's them into pure alcohol, stains with 

 hydrochloric acid carmine, and brings them gradually into 

 glycerin. 



Similarly ZOJA (Arch. f. mik. Anat., xlvii, 1896, p. 218) 

 and ERLANGER (ibid., xlix, 1897, p. 309). Zoja stained with 

 Bismarck brown and examined in dilute glycerin ; Erlanger 

 made paraffin sections and stained with iron ha3matoxylin. 



KOSTANECKI and SIEDLECKI (ibid., xlviii, 1896, p. 184) 

 employed concentrated sublimate solution, or 3 per cent, 

 nitric acid, or mixtures of these two, for ovarian ova. 



I fancy the best fixative for ova furnished with their cap- 

 sules will be found to be thfit of GILSON CARNOY-LEBRUN 

 ( 84) ; see CARNOY & LEBRON, La Cellule, xiii, 1897, p. 68. 

 After fixation the ova are carefully brought into 80 per cent, 

 alcohol, in which they are preserved. Imbedding should be 

 carefully done, as recommended for the ova of Amphibia 

 ( 600), but they ought not to remain in the pure paraffin 

 for more than a minute to a minute and a half. But these 

 authors prefer the celloidin method. At least six weeks' 

 soaking in the different strengths of celloidin will be neces- 

 sary to ensure penetration. They stain with iron hasma- 

 toxylin. 



Echinodermata, Ccelenterata, and Porifera. 



See the paragraphs treating of these groups in the chapter 

 on " Zoological Methods." 



