56 TAXIDERMY AND MODELLING 



no avail against the mildew. Examine the water from day to 

 day, and, when coloured by the bichromate, throw away, and 

 add fresh water with the same proportion of mercury as before. 

 After about a month the water will scarcely be tinted at all, 

 and will not require to be changed so frequently; nevertheless, 

 it must be watched, and changed as occasion requires, and the 

 subject afterwards preserved definitively (see Formol, p. 46). 



This formula possesses a decided advantage over alcohol, 

 inasmuch as it toughens and preserves the specimen equally 

 well, without causing the slightest shrinkage or objectionable 

 hardening, and, managed as directed, little loss of original 

 colour takes place. 



Alum. — This is one of^the oldest substances known to 

 the naturalist preparator, and although, to the taxidermist, its 

 use is somewhat limited as a preservative, yet for certain 

 purposes nothing can take its place. To the biologist it 

 is said, although superseded by many other things, to be 

 of service for the preservation of Medusae, and Lee, quoting 

 Pagenstecher, writes : — " Take two parts of common salt 

 and one of alum, and make a strong solution. Throw the 

 animals into it alive, and leave them there for twenty-four to 

 forty-eight hours. Preserve in weak alcohol. A saturated 

 solution of alum in sea-water preserves very well the forms of 

 Salpid(S, Medusce, Ctenophora, and other pelagic animals. It 

 constitutes a preservative medium in which the objects may 

 remain till wanted." 



44. — Hardening and Preserving Solution (M.B.) 



Alum . . . . . . ) Equal 



Nitre (saltpetre) . . . . / parts 



Make as a saturated solution with hot water, and allow to cool before use. 



Borax and Boracic Acid. — A preparation of borax is sold 

 by the Patent Borax Company, who claim special preservative 



