. Science-gossip . the tubes, andmuch valuable information obtained regardingtheir growth. Use a low-power object-glass, notless than one-inch. The convexity of the tubesdoes affect the image, but on the line along thecentre of the tube sufficient view will often beobtained, and the tube can be turned all roundfor examination. Before putting a tube underthe microscope fill up with water and insert thecork until the surplus water overflows. Thecontents of the tube may then be examinedwithout disturbing the position of the desmidsgrowing inside. To facilitate the examinationof the tubes under th
. Science-gossip . the tubes, andmuch valuable information obtained regardingtheir growth. Use a low-power object-glass, notless than one-inch. The convexity of the tubesdoes affect the image, but on the line along thecentre of the tube sufficient view will often beobtained, and the tube can be turned all roundfor examination. Before putting a tube underthe microscope fill up with water and insert thecork until the surplus water overflows. Thecontents of the tube may then be examinedwithout disturbing the position of the desmidsgrowing inside. To facilitate the examinationof the tubes under the microscope, make asmall table (to rest on stage of microscope) out ofa piece of cigar-box wood, about four inches longby two and a-half inches wide, with a narrowpiece half an inch wide, glued at right it the tube rests when the microscope isinclined. Cut a round hole one inch in diameterin centre to allow light from mirror to passthrough, (See fig. 4.) To transfer small quantities of desmids from. Fig. 4. tubes to slides a small pipette made with a childsfeeding-bottle rubber teat on end will be foundvery handy. These small pipettes can be obtained SCIENCE-GOSSIP. 325 from chemists ready-made and are known asmedicine droppers. It will be found by spending a few hours collectingas above described that sufficient material has beenobtained to keep anyone well employed for monthsin examining the desmids. It has been a matter ofgreat astonishment to find what a large number ofdifferent species may be obtained from a neigh-bourhood usually undreamt of as being so of the types are very beautiful and can only beseen with quarter-inch or one-sixth-inch objectives. If after some time any of the tubes show signs ofbecoming stagnant, all that is usually necessary isto aerate them by means of the pipette. Put theinstrument down to the bottom of tube andcompress the ball several times, being careful notto use too much force or you may dischargethe contents int
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