PRESERVATIVE FLUIDS. 223 



hydroid zoophytes, with, tentacles expanded, by adding \ / 

 spirit of wine, drop by drop, to the salt-water cell in 

 which they are confined. Animals should be killed 

 in this way as soon as possible after capture. 



A plan of mounting objects in a mixture of balsam 

 md chloroform is described by Mr. Wm. Henry Heys 

 in the Microscopical Journal : Take a quantity of 

 the oldest balsam procurable, and place it in an open 

 ^lass cup, and mix with it as much chloroform as 

 will make the whole quite fluid, so that a very small 

 quantity will drop from the lip of the containing 

 vessel. Then put this prepared balsam into long thin 

 half-ounce phials, and cork and set them aside for at 

 least a month. The advantage of having the medium 

 ^eady-made is, that there is no waste, and none of the 

 usual and troublesome preparation required for putting 

 up objects in Canada balsam; if it has stood for 

 some time, it loses the yellow tinge which is observable 

 ji most samples when first mixed, and, moreover, air- 

 3ubbles escape more readily. 



Groadby's fluids are cheap and efficient for preserving 

 ind mounting animal structures. The following are 

 lis formulae : 



Take for No. 1 solution, bay salt, 4 oz. ; alum, 2 oz. ; 

 ;orrosive sublimate, 2 grains ; boiling water, 1 quart : 

 nix. For No. 2 solution, bay salt, 4 oz. ; alum, 2 oz. ; 

 corrosive sublimate, 4 grs. ; boiling-water, 2 quarts : 

 nix. 



The No. 1 is too strong for most purposes, and should 

 mly be employed where great astringency is needed to 

 *ive form and support to very delicate structures, 

 ^o. 2 is best adapted for permanent preparation ; but 

 leither should be used in the preservation of animals 

 containing carbonate of lime (the mollusca), as the 

 ilum becomes decomposed, and sulphate of lime pre- 

 cipitated. For the preservation of crustaceans use the 

 ;ollowing : 



Bay salt, 8 oz. ; corrosive sublimate, 2 grs. ; water, 

 L quart : mix. 



The corrosive sublimate is used to prevent the 

 jroTvth of vegetation in the fluid; but it also pos- 



