374 On Preserving brittle specimens in Botany and Zoology. 



bered Boucherie's experiments with the same substance in giving 

 flexibility to wood. The principle that a substance which is 

 flexible when moist, will remain permanently moist, and therefore 

 permanently flexible, when impregnated with a deliquescent salt, 

 is so obviously true, that it needed no experiments to convince me 

 of its applicability to the fragile plants above mentioned, and to 

 many other specimens in natural history; but as practical diffi- 

 culties often occur in the application of correct principles, I have 

 tested the process by numerous experiments in which chloride 

 of calcium was employed to give flexibility to various vegetable 

 and animal products, and the results have fully equalled my ex- 

 pectations. My specimens of Amphiroa, Jania, Corallina, &c, 

 after being impregnated with this salt, and then exposed for 

 months to the air, can be handled as freely as if just taken from 

 the water, and they permanently retain nearly the utmost degree 

 of pliability they are capable of receiving. Species of dry, crisp 

 and brittle Lichens when treated in the same way became soft, 

 elastic and flexible, so as to bear very rough handling with per- 

 fect impunity. Many of the common Algse which shrink much 

 in drying, and therefore assume a very unnatural appearance, and 

 besides are apt either to become cracked or torn, or to wrinkle 

 up the paper to which they adhere, retain after immersion in this 

 salt nearly their normal degree of distension, and preserve a 

 much more natural appearance than when dried in the usual way. 

 Many dried specimens of plants, whose leaves, flowers or fruit 

 dropped off almost at a touch from specimens in my herbarium, 

 became permanently pliable when immersed for a short time in 

 a solution of chloride of calcium, and could then at any time be 

 handled freely, while their appearance was in no degree injured. 



In the animal kingdom, the results obtained in restoring per- 

 manent flexibility to dry and brittle specimens of Crustaceans, 

 Insects, Gorgonias, Sponges, &c. were equally satisfactory, and 

 have convinced me that almost every naturalist will, in his own 

 department, find many useful applications for this process. 



The mode of application which I have employed is to immerse 

 the dry specimen for some time in a neutral saturated solution 

 of chloride of calcium (which any one can make for himself by 

 saturating hydrochloric acid with marble), and then after the spe- 

 cimen has become sufficiently softened to bend easily, remove it 

 and let it drain in the open air. In some cases where the speci- 

 mens do not imbibe the salt readily, it is well to soften them in 

 warm water before immersion in the salt. A speedy impregna- 

 tion will then take place, after which the specimens, if plants, 

 may be subjected to moderate pressure in the usual way, and 

 restored to the herbarium ; while other specimens may be kept 

 on shelves, or in any way usually employed for similar objects, 



