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INTRODUCTION. 



injection-fluid contained in the bottle c, to which a mercurial manometer is attached. From 

 this an exit caoutchouc tube passes, which is attached to the cannula fixed in the artery. The 

 pressure-bottle a rests on a wooden support, which is raised by means of a screw, and in this 

 way sufficient pressure is obtained. In injecting with any pressure-apparatus, begin with a 

 pressure of one inch of mercury, and slowly increase it to four inches. Of course if a gelatine 

 mass be employed the bottle c must be kept warm, by placing it in warm water to keep the 

 gelatine in a fluid condition. 



Before beginning the injection, the cannula and the exit-tube from c must, of course, be 

 filled with the injection-mass, to avoid the entrance of air. This apparatus is expensive, and 

 therefore an apparatus that one can make for himself is to be preferred ; such as the following 

 simple mercurial injection-apparatus (fig. 25). It works on exactly the same principle, and 



Fig. 25. SIMPLE MERCURIAL INJECTION-APPARATUS. 



fig. 25 explains itself. One of the bulbs (c), containing the mercury, is stationary, whilst 

 the other (A) rests in a wooden framework, or shelf, which moves freely in a slot (D). 



The part of this movable shelf which is fixed in the slot is so made that it works very 

 freely, and when it is loaded at the free end of the horizontal arm, it becomes self-fixing at 

 any height. The pressure is very easily regulated by raising or depressing the movable shelf 

 (A). By means of a divided, or Y-shaped tube, two injection-fluids (B, R) may be used simul- 

 taneously. This arrangement, I find, works admirably. 



Simple Water Pressure-apparatus. Mercury is not always to be obtained, hence it is 

 sometimes convenient to employ water-pressure. Satisfactory results are not obtained by 

 connecting a water-tap to a system of pressure-bottles. The following arrangement (fig. 26) 

 is simple, cheap, easily made, and effective. It consists of a bottle, c, which holds the injection 

 mass, a much larger glass bottle, B, with a manometer (M) attached ; and communicating 



