Edward R. 8peyer 181 



In addition, Bonier found it necessary to open the bodies of the 

 larger forms before preparation, so that the method is very long, and 

 glycerine preparations are neither permanent nor very satisfactory. 



For quicker, more permanent, and equally satisfactory mounting, the 

 living insect is placed on a glass slide and a cover-glass (large for large 

 objects) is placed over it. A few drops of Sulphuric Ether are run beneath 

 the cover-glass, and the ether allowed to evaporate until the pressure 

 of the cover-glass forces out a portion of the contents of the insect; 

 their escape takes place through minute interstices in the chitin of the 

 head, and extremity of the abdomen. For large objects, it is necessary to 

 add a little pressure by means of a needle. The slide is then flooded 

 with Absolute Alcohol, and the cover-glass removed with a fine needle, 

 carefully. 



In the majority of cases the object sticks either to the slide or cover- 

 glass, and if sufficiently cleared, as is often the case with small insects, 

 may be mounted in balsam, as described below. The time taken by this 

 process does not exceed 5 minutes. 



If, however, clearing with Potash is demanded, the object, after the 

 above treatment with ether and absolute alcohol under the cover-slide, 

 is first hydrated, through the alcohols, into distilled . water, cleared in 

 2 per cent. Potash Solution, and again dehydrated through distilled 

 water to Absolute Alcohol. To the latter, drops of Turpineol are added 

 slowly, and finally the object, after immersion in pure Turpineol, is 

 mounted in Canada Balsam (Xylol Solution). 



The time taken over this method is roughly as follows: 



Hours Minutes 

 Ether-fixation and Hydration 20 



Clearinsr in 2 per cent. Potash Solution 3 



Deliydration 20 



Final Clearing in Turpineol and Mounting 5 



Total 3 45 



The objects, after treatment with ether, are flat, and therefore require 

 considerably less time in dehydration, hydration, and clearing with 

 potash, than in Borner's method. 



The final clearing reagents. Clove Oil and Xylol, are unsuitable for 

 these preparations, as distortion and contraction are liable to result, 

 especially after the use of potash. These inconveniences are readily 

 surmounted in their substitution by Turpineol. Chitin-stains, such as 

 "orange," are strongly deprecated. 



A number of insects may be treated with the ether on the same 



