THE MICROSCOPE. 197 



He also exhibited Abbe's new illuminating apparatus. 

 There being no further business the meeting was declared in- 

 formal. 



Meeting of December 8th, 1882. 



Dr. R. Tilley gave an account of the theory of the develop- 

 ment and life history of the blood corpuscle as advanced by Dr. 

 Richard Norris, of Birmingham, England. 



The chief points were as follows: There exists in the blood an 

 absolutely colorless corpuscle, and others of gradually increased 

 shades until we reach the extreme red color. 



The colorless disc is the young corpuscle just thrown into the 

 blood channels from the lymphoid organs. 



The extreme red corpuscle is the corpuscle approaching its dis- 

 solution. 



The colorless disc is invisible because it is of the same specific 

 gravity and index of refraction as the plasma. 



These discs can be rendered visible by various reagents and 

 mechanical devices. 



The formation of the fibrin of the blood is due to the coalescence 

 of these colorless discs. 



A discussion followed the reading of the paper entered into by 

 Dr. Curtis, Mr. Fellows and others. 



Dr. Tilley succeeded in giving a fine demonstration of the 

 presence of the colorless corpuscles in the blood, after which the 

 meeting adjourned. 



Selecting and Arranging Diatoms. — Mr. J. Chalon lately 

 described his method of selecting and mounting diatoms, before the 

 Belgium Microscopical Society. He picks them up with a hog's 

 bristle, 4-5 mm. in length, dipped in glycerin, which causes the 

 frustules to adhere to the bristle. The cover-glass upon which the 

 diatoms are to be arranged is coated with a thin layer of glycerin, 

 by .placing a drop of glycerin in 25 parts of alcohol upon it. The 

 alcohol evaporates and leaves the glycerin. This retains the diatom 

 in place, and when all are arranged, the cover-glass is heated to 

 drive off the glycerin, when the diatoms remain firmly attached to 

 the glass. — Ex. 



