USE OF THE MICROSCOPE IN BOTANY. 2*J 



duct ending at its finely-pointed extremity. We are 

 here reminded of the analogous case of a viper's 

 tooth in the animal kingdom. The phenomenon of 

 cyclosis, of which I have already spoken, takes place 

 probably in all kinds of hairs. Mr. Wenham says, 

 " The difficulty is to find exceptions, for hairs taken 

 alike from the loftiest elm of the forest, to the Humblest 

 weed that we trample beneath our feet, plainly exhibit 

 this circulation." To witness it, however, very high 

 powers of the microscope and great care are neces- 

 sary. In your examination of hairs, remember to tear 

 off a part of the cuticle from which they grow. If you 

 take hold of the hair itself, it will be almost sure to 

 break ; place the piece in a drop of water, with a thin 

 glass covering, and the forms of the various kinds will 

 reveal themselves. 



CHAPTER III. 



USE OF THE MICROSCOPE IN BOTANY (continued}. 



You will, no doubt, be much interested in examining 

 the structure of the hard portions of plants, such as 

 the stems, roots, seeds, &c. In many cases you will 

 find a sharp knife or razor sufficient for making sec- 

 tions of the parts you wish to study ; such substances 

 as the stony fruits of various trees require a more 

 expensive apparatus in order to prepare them for 

 investigation. I shall therefore take no notice of 

 these hard substances at present. You must take care 

 to prepare the stems or roots before you make your 

 sections ; if the wood be green, you must soak it for 

 some days in strong spirit, in order to get rid of any 

 resinous matter it may contain. After this, let the 



