SPERM ATOLOGIOAL METHODS. 339 



SCHOTTLANDEB (Arch, f. mik. Anat., xxxi, 1888, p. 426 ; Zeit. f. wiss. 

 Mik., v, 4, 1888, p. 515 cell-division in the corneal endothelium). 



644. Cytology of the Ovum (Ascaris}. 



VAN BENEDEN (Arch, de Biol., iv, 1883, p. 279). 



CABNOY (La Cellule, ii, 1, 1886, pp. 17, 18 ; iii, 1, 1886, p. 6 ; iii, 2, 

 1887). 



VAN BENEDEN et NEYT (Nouv. Rech. sur la Fee., &c., separate, 1887, or 

 Bull. Acad. roy. d. Sc. de Bruxelles, 1887, iii ser., xiv ; also Journ. Roy. 

 Mic. Soc., 1888, p. 508). 



BOVEKI (Zellen-Studien, in Jen. Zeit. f. Naturw., xxi, 1887, p. 423, or 

 separate ; also Journ. Roy. Mic. Soc., 1888, p. 664). 



ZACHABIAS (Anat. Anz., iii, 1888, p. 24 ; also Journ. Roy. Mic. Soc., 1888, 

 p. 663). 



VAN GEHUCHTEN (ibid., p. 237). 



KULTSCHITZKY (Arch. f. mik. Anat., xxxi, 1888, p. 567) recommends for 

 fixing a mixture of 3 parts of acetic ether with 1 part of absolute alcohol. 

 Clears for mounting in concentrated acetic acid, and mounts in a mixture of 

 acetic acid and balsam. An excellent resume of the technical part of these 

 papers is to be found in Zeit. f. wiss. Mik., v, 3, 1888, p. 367. 



Other Ova. 



HEBTWIG, 0. (Morph. Jahrb., x, 1884, p. 338, Rana). 



HEETWIG, 0. and E. (Jen. Zeit.f. Naturw., xix, 1885, p. 124). Fecunda- 

 tion of Strongylocentrotus (Echinodermata). Careful study of cell-anaes- 

 thetics. Abstracts in Zeit. f. wiss. Mik., iii, 4, 1886, p. 505, and Journ. 

 Roy. Mic. Soc., 1887, p. 835. 



BOVEBI (Zellen-Studien, iii [Echinodermata], in Jen. Zeit. f. Naturw., 

 xxiv, 1890, p. 314, or separate). 



645. Spermatological Methods. One of the great difficulties here 

 met with consists in getting a sufficiently rapid fixation of spermatids and 

 spermatozoa, some of which are probably the most rapidly contracting ele- 

 ments that exist. For fresh material, teased on the slide, strong solution of 

 permanganate of potash is very useful, being the most rapidly fixing agent 

 that I know of. Tincture of iodine is also useful. For staining, gentian 

 violet or dahlia should be used as far as possible, as they have a special 

 affinity for spermatic cells. For mounting aqueous preparations, solution 

 of Ripart and Petit, or some such mercurial fluid as those of Pacini, are in- 

 dicated. 



As to the Nebenkern, which is here so important an element, see ante, 

 639. 



Besides the papers quoted for cytological methods, and besides the nume- 

 rous publications of v. LA VALETTE ST. GEOEGE, in Arch. f. mik. Anat., see 

 the following : 



CAENOY (La Cellule, i, 1885, p. 209, Arthropoda). 



GILSON (ibid., i, 1885, pp. 40, 56, 58, 87, 121, 141, and ii, 1886). Here is 

 a useful fixing medium for fresh teased preparations iodised osmic acid 



