MICROSCOPICAL DIAGNOSIS. 21 



If it is desirable to mount the section in some watery medium, 

 it will be necessary to make a ring or cell upon the slide. The cell 

 may be made with white zinc, Brunswick black, or gold size. The 

 slide is placed upon a turn-table, and with a sable brush a cell is 

 made a trifle smaller than the diameter of the cover, so that the edge 

 of the cover is in the center of the ring of cement. A number of 

 these cells can be kept on hand, and when one is wanted for use, 

 it is only necessary to apply a little fresh cement to the outer Half 

 of the ring, in order that the cover may adhere to it at once. After 

 the specimen has been placed in the cell with, the mounting fluid 

 in which the specimen has rested for some time and the cover 

 applied, another ring is spun around the edge of the cover in order 

 to seal up the cell. The various methods of making cells cannot be 

 discussed here. They are all useful, and many of them beautiful. 

 Deep cells can be made by using rings of glass, or of wax, or, as 

 Mr. Griffith has suggested, of curtain rings. The details for this 

 work must be sought for either in works devoted exclusively to 

 mounting, or in the various microscopical journals published at 

 home and abroad. 



INJECTING. 



It is impossible to describe the art of making satisfactory injec- 

 tions. Anything approaching perfection is attained only after long 

 practice and careful attention to the many minute particulars. A 

 small brass syringe, supplied with a stopcock and several nozzles of 

 different sizes, answers every purpose; or an injecting apparatus 

 may be made as .represented in figure 7. A, represents a pail 

 partly filled with water, which can be raised or lowered, to regulate 

 the pressure, by fastening one end of a cord to the handle of the 

 pail, and then passing the other end over a pulley fastened to the 

 ceiling of the room; b is a bottle with an air-tight fitting cork, 

 pierced by two short glass tubes; c is a bottle partly filled with the 

 injecting fluid. Through the cork of this bottle are two glass 

 tubes, one of which is short, while the other reaches nearly to the 

 bottom of the bottle; d is a brass nozzle with a stopcock; r is rub- 

 ber tubing, which unites the different parts as seen in the figure. 

 A Y-shaped glass tube can be inserted midway in the rub- 

 ber tube between the two bottles, so that two bottles 

 of the injecting mixture can be attached to the one 



