oG 



A IIALF-HOUK WITH TilE 



CHAPTER IV. 



A HALF-HOL'R WITH THE MICROSCOPE 

 AT THE POXD-SIDE. 



Cisterns, ditches, ponds, and rivers, contain nume- 

 rous objects to interest the microscopic observer. 

 Some of these objects float on the surface of the 

 water ; others are found swimming about in the 

 midst ot the water ; whilst the greater number 

 are found at the bottom. In collecting objects 

 from fresh water, little bottles may be used, and a 

 common spoon or small net employed for collecting 

 them. Where the objects are only few, large 

 quantities of the water should be allowed to stand, 

 and the whole poured otF, with the exception of a 

 table-spoonful or two, which may be then placed 

 in a wine-glass. A little of the sediment may be 

 taken up in a pipette or dipping-tube, and con- 

 veyed to the animalcule-cage, and the cover having 

 been put on, it may be placed under the Micro- 

 scope. If the objects are moving about too rapidly, 

 the cover may be pressed down till they are secured. 

 They may be first sought out with a low power, 

 and when it is washed to examine them more 

 closely, a higher power may be put on. 



Of all the forms of microscopic plants which 

 are found in fresh water, those belonginsf to the 

 families of desmids and diatoms are most interest- 

 ing. We have already spoken ot plants consisting 

 of one cell, and these also consist of one cell ; but 

 they have this peculiarity, that their cells are 

 divided into two equal parts, each part having the 

 f.aiiie form as the other. The desmids are dls- 



