BAYBERRY TALLOW. 153 



arrived at in from one to six hours, according to the quality 

 of the paraffin. The mass then becomes brownish-yellow, and 

 after cooling shows an unctuous or soapy surface on being cut. 

 The melting point will be found to have risen several degrees. 

 BRASS (1. c., p. 300) recommends the use of paraffin that 

 has been kept for some years, as such has less tendency to 

 crystallise than new paraffin. In this I concur. 



FOETTINGEE recommends (Arch, de BioL, vi, 1885, p. 124) a somewhat 

 complicated treatment with caustic potash, in which I have no faith (it was 

 tried by one of the writers of the Traite des Meth. Techn., during the pre- 

 paration of that work). 



280. Paraffin Mixtures and other similar Masses. Of these, 

 the only one that I think can be recommended for a moment 

 is SCHULGIN'S paraffin with a little cerisin (this is evidently 

 what Schulgin means by " ceresin") . Or instead of cerisin, 

 white wax (see Zool. Anz., 1883, p. 21). 



BRASS (Zeit. f. wiss. Mik., ii, 1885, p. 301) recommends four 

 to six parts of white wax to 100 of paraffin. Sections may be 

 cleared with benzin. 



Wax and Oil (STEICKEE'S formula, KOY'S formula, Handbuch d. 

 Geweblehre, pp. xxiii and 1202). 



Wax and Oil (FOSTER and BALFOUE'S formula, Elements d' Embryologie, 

 p. 296, 1877). 



Paraffin and Axunge (HUXLEY and MARTIN'S formula, FOSTER and 

 BALFOUE'S formula), ibid. 



Paraffin and Tallow (SEILER'S formula, Compendium of Micro- 

 scopical Technology, 1881, pp. 47, 48 ; Journ. Roy. Mic. Soc., N.S., i, 

 p. 840). 



Paraffin and Vaselin (FEENZEL'S formula, Zool. Anz., 1883, p. 51). 



Spermaceti and Castor-Oil (KLEINENBEEG'S Elements d'Embryologie 

 (FOSTEE and BALFOUE), pp. 296-8). 



Spermaceti and Cacao-Butter (FOSTEE and BALFOUE, ibid, p. 296). 



Spermaceti, Castor-Oil, and Tallow (STEASSEE'S Morph. Jahrb., v, 

 1879, p. 243 ; Journ. Roy. Mic. Soc., N.S., i, p. 840). 



Cacao-Butter, pure, is still used by some histologists. It melts some- 

 what under 35 C. The objects may be prepared by penetration with clove 

 oil, which may also be used for removing the mass from the sections. 



281. Bayberry Tallow (Myrtle Wax, Vegetable Wax, Japan 

 Wax). There appear to be more than one sort of vegetable wax in the 

 market. That called Bayberry Tallow (see Journ. Roy. Mic. Soc., 1885, p. 

 735) is a product of the North American bayberry tree, Myrica cerifera. 

 Another sort, sold under the name of Myrtle wax or Japan wax (see op. cit., 

 1888, p. 151), is the product of Rhus succedanea. It is this latter sort that, 

 by all accounts, should be used for imbedding. 



