316 ENTOMOLOGY. 



which it may remain for a day or two. Fit a cylinder of soft wood 

 into the well of the section- cutter; split this cylinder through the 

 middle, and cut a groove in one or both of the half-cylinders suffi- 

 ciently large to admit the object without pressure; put the two pieces 

 together with plenty of thick shellac, and tie them with a thread. 

 When the shellac is quite hard, which will be the case in a day or 

 two, place the cylinder in the section-cutter, and, after soaking the 

 wood with warm water, sections the 5^5 of an inch in thickness, or 

 less, may readily be made. 



Should the shellac prove so opaque as to interfere with a proper 

 examination, a drop of borax solution will immediately remove this 

 difficulty. (Amer. Month. Micr. Journ., i. (1880) p. 8.) 



Mounting Gizzards of Insects. Dr. T. J. Sturt kills the specimen 

 with a drop of benzine, cuts off the extreme end of the hind body, 

 removes the head, cuts off the whole intestine, and puts it in a 1 oz. 

 vial with five or ten drops of liquid potash. After it has stood about 

 half an hour, partly fill with water and shake it well to detach the 

 muscular coat and tracheae; then slit it up, wash, and adjust on a 

 slide. Drain away any moisture, apply a drop of carbolic acid, and 

 put on the thin glass. After a few minutes this will absorb all 

 moisture and render it quite transparent. If it does not, put a drop 

 of acid at the edge and tilt the slide to drive off the first acid; then 

 put a little balsam on the edge, tilt the slide, warming it to render the 

 balsam more limpid, and it will gradually take the place of the acid, 

 the lines of demarcation between the two being distinctly visible. 

 (English Mechanic, 1882, 282.) 



Preparation of the Intestine of Insects. According to Dr. J. Frenzel, 

 chromic acid is not suitable for the examination of the intestine of 

 Arthropoda. A mixture of nitric acid and an alcoholic sublimate 

 solution gave satisfactory results. The strength of the alcohol and 

 the amount of sublimate in solution do not appear to matter. The 

 author used 80 per cent, alcohol with sublimate half saturated. No 

 particular caution is necessary as to the amount of acid; a drop too 

 much or too little doing no damage. To the above solution a drop of 

 concentrated sulphuric acid is added to every one or two cubic centi- 

 metres. The presence of this acid induces a quicker penetration of 

 the preservative fluid into the tissues, and hinders the formation of 

 insoluble mercurial compounds. The more acid the solution and 

 the smaller the piece of tissue the shorter the time it is left in the 

 fluid. For pieces about the size of a pea, five to ten minutes are quite 

 sufficient. After hardening in sublimate, alcohol is advantageous. 

 The tissue is washed and left in 90 per cent alcohol. (Archiv fiir 

 Micr. Anat., 1885, 229.) 



