110 GENERAL HISTORY OF THE INFUSORIA. 



into three to five or six parts at one extremity, to be fixed by the other in a 

 piece of cork, and held in a common needle-holder. Such split hairs are com- 

 mon enough in an old shaving-brush ; but the divergence of the split portions 

 should be so slight that, until pressed upon, the hair should appear single and 

 unbroken. He has also found entii^e hairs very useful when set in needle- 

 holders in a similar manner. The split haii's act like forceps, expanding by 

 pressure so as to embrace the object, and closing upon it by their elasticity 

 when the pressure is withdrawn. 



To select certain portions of a collection of Diatomeae from others. Dr. 

 Carpenter gives these directions {The Microscope, p. 340) : — " Either of the 

 two following modes may be put in practice. A small portion of the sedi- 

 ment being taken up in the dipping-tube, and allowed to escape upon the 

 slide, so as to form a long narrow Hne upon it, this is to be examined with 

 the loAvest power with which the object we ai'e in search of can be distin- 

 guished ; and when one of the specimens has been found, it may be taken 

 up, if possible, on the point of the hair, and transferred to a new slide, to 

 which it may be made to adhere by first breathing on its surface. But if it 

 be found impracticable thus to remove the specimens, on accoimt of their mi- 

 nuteness, they may be pushed to one side of the slide on which they are 

 Ijdng ; aU the remainder of the sediment which it is not desired to preseiwe 

 may be washed off" ; and the objects may then be pushed back into the middle 

 of the slide, and mounted in any way that may be desit^d." See Goring and 

 Pritchard's Microscopic Illustrations, Microscopic Cabinet, and Micrographia 

 for much original information on these matters. 



