334 



MICROSCOPIC ANIMALS AND PLANTS 



[Ch. X 



i 



!l:i : J 



u 

 A B 



Fig. 200. Pipettes 

 for Liquids and for 

 Specimens. 



A Pipette for liquids. 

 This is about one-third 

 size. 



B Pipette for hand- 

 ling ova and other deli- 

 cate specimens. 



1 The rubber bulb 

 tied to the glass part. 

 It is about natural size. 



2 Glass rod. The 

 upper end is fluted so 

 that the rubber bulb 

 will not come off, and 

 the lower end is care- 

 fully smoothed by heat- 

 ing. To prevent small 

 ova and other objects 

 getting into the bulb, 

 some fine gauze may be 

 tied over the upper end. 



3 Soft rubber tube 

 over the lower end. 

 This is not absolutely 

 necessary, but the soft 

 rubber is less liable to 

 injure delicate objects 

 than the hard glass. 



mens may be mounted in glycerin, glycerin jelly, 

 or balsam. Glycerin jelly is the most satisfac- 

 tory, however. 



Collection and Study of Microscopic 

 Animals and Plants 



§ 520. Collection of material. — There are 

 many microscopic forms in nature that need no 

 other preparation than mounting on a glass 

 slide. If low powers are used a cover-glass 

 may be omitted, but if high powers are to be 

 used a cover-glass must be put over the object 

 to protect the objective as well as the object, 

 and to make the optical corrections of the ob- 

 jective perfect (§ 460). 



The easiest places to find things most in- 

 teresting and beautiful is in the water of pools 

 and along the shores of streams where the water 

 is quiet. Go to some pond or stream and along 

 the shore where it is shallow; take some of the 

 vegetation and the mud, put in a pail or dish, 

 and take to the home or laboratory. Put the 

 water and vegetation in a plate or other shal- 

 low vessel and put it in about the same light 

 that it had in nature. In a few hours, when the 

 mud has settled the conditions will be nearly as 

 in nature, and by the use of fine forceps or one 

 of the pipettes (fig. 190, 200), gather some of 

 the water with scrapings from some of the vege- 

 tation, or some of the water and mud. Put it 

 on a slide, cover and examine. There may be 

 much to see or very little. One must persevere 

 and finally there will come a kind of instinctive 

 knowledge where to find things. It is also a 

 good plan to use the tripod or other magnifier 

 and examine the dish. Often much can be seen 

 in that way, and one will get a hint where to col- 



