INFTTSORTAL ANIMAT.CItLKS. 109 



considered esseiitial. Txu-Hhria, in this condition, have often been 

 preserved by botanists, in collections of minute Alg'a3, and with very 

 little management ; but other families will require more care. 

 Having selected the creature you wish to preserve, remove it with a 

 fine pointed quill, and put it on a slip of glass, or other convenient 

 receptacle. By this means there will be but a small portion of water 

 surrounding it, which may be removed by some pointed pieces of 

 ragged blotting paper. When you have withdraviTi as much of the 

 water as possible from the specimen, the remaining moisture may be 

 readily e^'aporated, by placing the glass on the palm of the hand. 

 The Hydatinea may be best presei'ved when destroyed with strychnia, 

 and then rapidly dried. By what mode soever life may be taken 

 away, it is absolutely expedient that they should be speedily and 

 cai-efiilly dried, otherwise their bodies will be decomposed, gases 

 evolved, and the object will fail. 



I have seen a fine collection of dried specimens of Rotatoria, pre- 

 served by Ehrenberg between small discs of mica. These are very 

 portable and may be carried about in a pocket book. Each specimen 

 worthy of observation, had a ling of paper gummed to the mica. The 

 discs of mica were about three-eights of an inch in diameter. Several 

 of these discs were arranged in a row, and attached to a slip of mica 

 three inches long and one-eighth of an inch wide. 



Another way of mounting for the microscope dried Infusoria, is on 

 slips of plate glass, having a polished circular cavity, in which to 

 deposit the creatures. These may be numbered, or otherwise marked, 

 with a writing diamond, and a large collection of them arranged in a 

 very compact case. 



Possil Infusoria are best preserved in Canada balsam, under thin 

 slips of glass. (See Section X.) 



Infusoria, when simply dried, may be relaxed again by moisture, 

 and some of them will bear this o]ieration several times — the soft- 

 boflicd ones, however, only once. The general colour of Infusoria is 

 retained for a considerable time after they have been dried, but the 

 pigment of the eye is soon lost. It may be Avell to obsei've, that 

 when the preserved specimens are intended to illustrate the nutritive 

 system, they should be previously fed with coloming matter ; but for 

 observation on other organs, this is not advisable. 



