1893.] 



MICROSCOPICAL JOURNAL. 

 MICROSCOPICAL APPARATUS. 



293 



An Injecting Apparatus. — The best arrangement must pro- 

 vide — (1) that the apparatus be simple; (2) that the pressure be 

 capable of measurement; (3) that the pressure be under control 

 such that it may be increased gradually and maintained stead- 

 ily. Prof. Jas. Middlemass of Edinburgh, Scotland claims to 

 have alone accomplished these results and with the apparatus 

 herein described. 



Get a Woulff bottle with three necks (Fig. 1) or a wide- 

 mouthed bottle and india-rubber stopper with three holes. 

 Size, 8 oz. With a syringe introduce compressed air by one of 



the necks. By anoth- 

 er neck the pressure 

 is transmitted to the 

 bottle (Fig. 2) which 

 contains the injecting 

 fluid. By the second 

 neck, insert a small 

 graduated manometer 

 tube. Then, in the 

 bottom of this bottle put some mercury — enough to cover the 

 tube to the zero point on the manometer. The mercury may 

 be brought to the same height within the tube by sucking out a 

 little air. This bottle is now ready for use. 



In the glass tube which leads into the bottle is a three-way 

 stopcock (a). This is to obviate any deficiencies in the syringe 

 (which may be Higginson's syringe, an injection syringe or the 

 syringe of certain forms of aspirator). 



F'igure 3 shows the position of the stopcock when air is being 

 pumped into the bottle; Figure 4, that when the requisite 

 amount of pressure has been obtained; and Figure 5, that when 

 it is desired to reduce the pressure in the bottle. 



It is well, but not necessary, to have stopcocks on the tubes 

 leading away from the bottles (6, c). 



The manometer will measure the pressure in atmospheres, in 

 inches, or in millimeters as desired. Every thing about the ap- 

 paratus must fit perfectly air-tight. — Journal of Pathology and 

 Bacteriology. I, Hi. 



