ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 67<3 



be lifted out of the vessel, but floated from oue vessel to another. If they 

 are lifted out the tentacles become disarranged, and cannot again be put 

 right." 



Preparation of Insect Spiracles.* — Mr. F. Dienelt remarks that in most 

 beetles the spiracles are found on the upper part of the abdomen. Tho 

 insect should be turned on its back and cut across the thorax close to the 

 abdomen ; then turn again, and insert a sharp knife into the opening made, 

 and cut round the whole abdomen. As soon as there is room, insert a small 

 stick of soft wood sharpened to a flat point, by means of which the object 

 can be held securely while cutting. All the cutting should be done on the 

 lower side, so that a margin is left on the upper part, which can be trimmed 

 easily after the object has become softened in liquor potasste. Steeping 

 the insect in this fluid for a couple of hours will destroy all the viscera. 

 Now, hold the part down with the pointed stick, which for this purpose 

 is far superior to mounting-needles, and with a camel-hair pencil remove the 

 viscera and transfer the object to rain-water, removing this two or three 

 times to insure cleansing and to remove the last trace of potash. Keep on 

 brushing until it is certain that the object is clean, and then trim the edges 

 to suit before a final washing. If it be desired to mount the tracheaa 

 in situ, greater care is necessary in treating, but they show very well 

 through the skin. Or after most of the viscera have been removed, the 

 tracheae can be torn by a sawing motion with the back of the knife from the 

 spiracles and mounted separate. In mounting larvfe entire, they should 

 be left in liquor potassfe for a longer time; even a whole day without 

 injury. In cleaning, it is necessary to keep them in the position in which 

 they are to be mounted. Larvte of the Lepidoptera show best when mounted 

 ou the side. In preparing these, hold the larva under water with the 

 pointed stick, and clear out the viscera with a brush through the anal 

 opening by a rolling motion. After a start has been made the process 

 takes but a short time. Larvae will stand considerable pressure in cleaning, 

 but gentle manipulation of course answers best, especially in those covered 

 with hair. It is best to commence with the largest beetles or larvte one 

 can find. Larvae too large to be mounted entire ought to be opened along 

 the back to give the liquor free access. 



Twenty-seven grains of potassa fusa to one ounce of water acts but 

 slowly on the chitinous parts of insects, but very promptly on the viscera. 

 It is best kept in a paper-covered bottle, to exclude the light. 



Botanical Manipulation. t — M. P. Girod's ' Manipulations de Bota- 

 nique ' treats, in the first place, of the methods of using the Microscope, 

 reagents, &c. The rest of the work consists of a series of original diagrams 

 illustrative of the histology and anatomy of typical plants, from Dico- 

 tyledones to Algae, ending with cell-tissue for purpose of comparison with 

 unicellular organisms. Short notes explaining the methods of preparing 

 sections accompany the plates. 



Preparation of Plants in Alcohol.| — M. H. de Vries explains the great 

 brittleness imparted to fresh parts of plants by plunging them in alcohol in 

 the following way : — The alcohol penetrates first into the outer, aud only 

 gradually into the inner, layers of tissue. While the outer cells are killed, 

 the inner cells still retain all their turgidity. These inner still living cells 

 prevent the contraction of the cell-walls in the outer layers, and the latter 

 become, therefore, hardened while still in the stretched condition. While 



* The Microscope, vii. (1887) pp. 102-3. 



t Girod, P., ' Manipulations de Botaniquc,' 72 pp. and 22 pis., 8vo, Paris, 1887. 



i Maaudbl. v. Natuuiwetensch., 18S6. See Bot. Ztg., xlv. (1887) p. 31. 



