1900] MICROSCOPICAL JOURNAL 247 



Eucaine Hydrochloride as a Narcotizing Agent. 



GEORGE T. HARRIS. 



On commencing work upon any group, the question that 

 the naturalist has almost immediately to decide is that of 

 a suitable narcotic, as few groups permit of much work 

 without such an aid ; and, when permanent preparations 

 are desired, narcotization becomes almost indispensable. 

 Some forms contract so slowly that narcotization may to 

 a very large extent be dispensed with, and some energetic 

 killing agent applied at the outset ; but the percentage of 

 forms amenable to this treatment is very small, and the 

 microscopical naturalist may almost take it for granted 

 that any group he may elect to work upon in zoology will 

 require more or less complete narcotizing before he can 

 proceed to kill. It not infrequently happens that even 

 when the quest for a suitable anaesthetic has been success- 

 fully accomplished, trouble will be encountered with the 

 killing agent, as the most suitable "fixer" for the forms 

 under observation may precipitate the narcotic, or in its 

 turn be precipitated by the narcotic. Enough has been 

 said to show that the problem of narcotization is one of 

 paramount interest to the specialist. 



When cocaine hydrochlorate came into use, it was found 

 to be applicable to so many groups that it practically oc- 

 cupied the place of an universal narcotizer, as many forms, 

 which previous to its introduction had been ansethetized 

 with difficulty or not at all, were now comparatively easy 

 to prepare. Yet even this failed signally with some 

 groups, among them being many genera of the Protozoa. 

 With Vorticellidae it was practically useless; for one or 

 two years I labored patiently, trying to obtain perfect 

 mounts with cocaine, but to no purpose. In some species 

 the cocaine acted perfectly as far as the stalk was con- 

 cerned, and failed dismally where the ciliary wreath was 

 in question, and in other species the converse took place. 



