CHAPTER XXIX. 377 



rated solution of thionin, and washes out with alcohol of 70 per 

 cent. Said to be specific for embryonic cartilage. 



VASTARINI-CRESI (Aft. Accad. med.-chir. Napoli, 1907, p. 4) 

 stains sections of embryonic cartilage with borax carmine, then 

 with muchsematein (alcoholic solution without acid), and then with 

 Orange G. in alcohol. 



BAYERL'S method for ossifying cartilage (Arch. mik. Anat., 1885, 

 p. 35) : Portions of ossified cartilage are decalcified as directed, 

 555, cut in paraffin, stained in Merkel's carmine and indigo- 

 carmine mixture, and mounted in balsam. 



MAYER (Grundziige, LEE and MAYER, 1910, p. 393) prefers to all 

 these resorcin fuchsin, 758, the precipitate being freed from iron 

 chloride by washing before dissolving in the alcohol. 



Aqueous solution of benzoazurin has been commended as a stain for 

 ossifying cartilage by ZSCHOKKE, see Zeit. wiss. Mile., x, 1893, p. 381. 



A process of BAUMGARTEN'S has been given, 388. 



MOERNER (Skandinavisches Arch. Physiol., i, 1889, p. 216 ; Zeit. wiss. 

 Mik., vi, 1889, p. 508) gives several stains for tracheal cartilage, chiefly 

 as microchemieal tests, for which see third edition. 



See also a critique of these methods by WOLTERS in Arch. mik. Anat., 

 xxxvii, 1891, p. 492 ; and on the whole subject of cartilage see SCHIEF- 

 FERDECKER'S Gewebelchre, p. 331. 



FUSARI (Arch. Ital. Biol., xxv, 1896, p. 200) makes sections of fresh 

 cartilage, puts them for twenty-four hours into 1 per cent, nitrate of 

 silver, washes, dehydrates, and exposes to the light in balsam. 



See also DISSE, Anat. Anz., xxxv, 1909, p. 318, a stain for dentine 

 (haemalum followed by a mixture of Saurerubin and Orange G) ; and 

 RETTERER and LELIEVRE, C. E. Soc. Biol., Ixx, 1911, p. 630. 



Skeletons of Embryos. 



779. Cartilaginous Skeletons of embryos (VAN WIJHE, Proc. K. 

 Akad. Wetensch. Amsterdam, 1902, p. 47) may be studied by staining 

 embryos for a week in a solution of 0-25 grm. methylen blue in 

 100 c.c. of 70 per cent, alcohol with 1 per cent, of hydrochloric acid. 

 Wash out in alcohol with 1 per cent, of hydrochloric acid until no 

 more colour comes away (about a week) and mount in balsam. The 

 cartilage remains blue, all the other tissues being colourless. 



Similarly, LUNDVALL (Anat. Anz., xxv, 1904, p. 219, and xl, 1912, 

 p. 639), using toluidin blue. Thionin blue also may be used. 



Similarly also BAKAY (Verh. Anat. Ges., 1902, p. 248), with Bismarck 

 brown (the embryos having been previously treated with nitric acid of 

 3 per cent.). 



For fish embryos, Professor E. S'. Goodrich, of Oxford, informs me that 

 thionin is excellent. 



For the Spalteholz method of clearing such preparations see 592. 



