The Microscope. 



269 



HOW TO PERMANENTLY PRESERVE. 



If desired to mount a speci- 

 men of blood a slide should be 

 prepared according to the sec- 

 ond met hod given above. When 

 the blood is dry the slide is 

 transferred to the turn-table and 

 a shallow ring of cement placed 

 upon it ; the slide is now gently 

 warmed and the cover-glass ap- 

 plied at once and sealed in 

 place. Or a slide, prepared as 



o © 



FIG. 4-Pus. A, before, and B, after the 

 action of dilute acetic acid. Ti e pus 

 corpuscle resembles the white blood- 

 corpuscle. 



above, can be exposed to the 

 fumes of a one per cent, solution 

 of osmic acid for a few minutes, 

 until the corpuscles are colored 

 and then mounted in balsam. 



FIG. 3— Showing relative size of red 

 blood-corpuscles of different animals. 

 1, musk deer, 2, horse. 3, mouse, 4. man, 

 5, whale, 6. elephant, 7, humming bird, 

 8, rheasant, 9, pigeon, r l0. snake, 11, 

 crocodile, 12, triton, 13, proteus. 



MICROSCOPICAL SOIREE. 



THE annual Soiree of the Biological and Microscopical Sec- 

 tion of the Academy of Natural Sciences, Philadelphia, 

 took place at the hall of the Academy on the evening of 

 December 3d, and in all respects was the most successful and 

 interesting one ever made by the section. In the main hall or 

 library and in the alcoves surrounding it, upon numerous and 

 well-lighted tables were arranged nearly two hundred micro- 

 scopes by various makers, American and foreign ; on the stages 

 of which were displayed an infinite variety of objects in the 

 mineral, vegetable and animal kingdoms, illuminated by all 

 the different methods, best calculated to show their various 

 structures and beauties. Each instrument was presided over 



