THE MICROSCOPE. 15 



tokrit is caused to rotate 5,000 times. This rapid rotation precipitates 

 to the outer end of the tube the red blood corpuscles, which are of 

 the highest specific gravity. Next to these will be arranged the white 

 corpuscles, which are heavier than the plasma, while the plasma 

 fills the remaining portion of the tube. A tube is also provided for 

 sputum, by means of which bacteria may be precipitated, thus in- 

 creasing the accuracy of a microscopic analysis. 



Slide and Cover-glass. The slide consists of a piece of glass one 

 inch wide and thige inches long, and is used to receive the object 

 to be examined. The cover-glass is a thin piece of glass, rectangular 

 or circular in shape. In cleaning slides and cover-glasses, tissue paper 

 or a linen towel may be used. They should always be seized by their 

 edges, never allowing the fingers to touch the flat surfaces. 



Student Microtome. 



Bausch & Lomb Optical Co., Rochester, N. Y. 



NOTE. Nearly all the illustrations of this manual are from electro- 

 types kindly loaned the author by the Bausch & Lomb Optical Company, 

 of Rochester, N. Y. Students and others desiring to purchase micro- 

 scopes and microscopic supplies will find this firm courteous in its deal- 

 ing's. The goods sent out by this house are reasonable in price and first- 

 class in quality. 



