as much turpentine from under the cover as is necessary; then drop the balsam, thinned with chloroform (see Chapter I.), upon the slide, letting the fluid touch the cover, when it will be taken in between the surfaces by capillary attraction; and after pressing the cover down it may be left to dry, or you may hold the slide over a spirit-lamp for a few seconds before pressing down the cover. If heat is not applied, they are much longer in drying but are more transparent. If made too hot the boiling disarranges the objects, and if carried too far will leave only the resin of the balsam, rendering it so brittle that the cover is apt to fly off by a fall or any jar producing sufficient percussion. Never lift the cover up, if possible, during the operation, as there is danger of admitting air. A few bubbles may appear immediately after mounting, but generally subside after a few hours, being only the chloroform or turpentine in a state of vapour, which becomes condensed.” [C] This applies to the more delicate ones, which will not bear transferring after being once spread out and dried. This method of preparing and mounting insects I can strongly recommend as giving first-rate results; but where the specimens are small they seldom need the soaking in caustic potash which larger ones must have. It is only necessary to leave them awhile in turpentine, especially when they have been first dried with gentle pressure between two glasses, and then mount with balsam in the ordinary way. Amongst the insect tribes there is abundant employment, especially for the lower powers of the microscope. But if the deeper wonders and beauties of the animal economy are to be sought out and studied, it is desirable that the various parts should be set separately, in order that they may receive a more undivided attention, as well as to render them capable of being dealt with under the higher powers. We will, therefore, briefly consider the treatment which the different portions require.