ON THE USE OF CARBON DIOXIDE IN KILLING 



MARINE ANIMALS. 



ALFRED G. MAYER. 



For several years I have been making use of sea-water charged 

 with CO 2 for producing anaesthesia in marine animals, thus en- 

 abling one to kill them in an expanded state. 



One of the soda-water siphon -bottles, sold in the market under 

 the trade name of "Sparklet Bottles," infilled with sea-water 

 and this is charged with CO 2 by means of the"" Sparklet bulb." 



This charged sea-water is then poured into a vessel containing 

 ordinary sea-water in which the marine animals are living, and 

 in a few moments they are completely narcotized, and may then 

 be killed in a fully expanded state by the addition of any killing 

 fluid. 



In some instances the CO 2 should be followed by the addition 

 of a small quantity of chloretone, but this appears to be neces- 

 sary only in the case of Siphonophorae wherein it entirely pre- 

 vents the casting off of the swimming bells. 



This simple method enables one to obtain excellent prepara- 

 tions for histological or for museum purposes of such delicate 

 marine animals as the medusse. It is also applicable to Crus- 

 tacea, Worms, Mollusca, etc. 



CARNEGIE INSTITUTION LABORATORY, 

 TORTUGAS, FLORIDA. 



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