340 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Fig. 91. 



to ten minutes; nitric-acid-alcohol (3HN0^ to 100 C^H^O), about six 

 hours ; alcohol, one to five minutes ; oil of cloves or origanum ; balsam. 



Gage's Injecting Jar.*— Prof. S. H. Gage's injecting jar (fig. 91) grew 

 out of the necessity for some simple and efficient apparatus for injecting 

 liquids (chloride of gold, nitrate of silver, nitric, chromic, osmic, and picric 



acids) which would be injured 



by or injiu'e an ordinary 



B . syringe. As will be seen, it 



is made on the principle of 

 an ordinary wash-bottle. It 

 is prepared by boring two 

 holes in the glass cover of a 

 fruit-jar or of an anatomical 

 specimen jar, and inserting 

 glass tubes, the pressure-tube 

 A just penetrating the cover 

 and the delivery-tube B ex- 

 tending nearly to the bottom 

 of the jar. Where the glass 

 tubes penetrate the cover they 

 are surrounded by rubber 

 tubing D, to render the joints 

 air-tight. The pressux'e is obtained by the use of an atomizer bulb, or, in 

 order that it may be constant, two bulbs are used, the second one being 

 covered with a net to prevent undue distention. The delivery-tube and the 

 cannula C are of glass, only enough rubber tubing being used to make the 

 delivery-tube outside the jar flexible. 



While this jar was designed for special liquids, it has been found excel- 

 lent for making fine injections with gelatin mass. With two bulbs, as in the 

 figure, a pressure of 40 mm. of mercury may be obtained ; this is sufficient 

 for most purposes. While water or mercury might be used to obtain the 

 pressure, as in the various forms of constant pressure apparatus, the 

 atomizer bulbs are preferred, as it is easier for the operator to control the 

 pressure and adapt it to the individual cases. 



Stein's Injection Apparatus. f — The injection apparatus used by Dr. 

 S. T. Stein is shown in fig. 92. In this instrument the required force is 

 derived from the action of compressed air upon a column of liquid, and it 

 consists accordingly of two parts — A the compression-pump, and B the 

 vessel which holds the liquid. The pump A, made of guttapercha, consists 

 of an air-bag m into which air is forced by means of a collapsible ball and 

 the two valves a and h. From m the air passes by the tube cf into B 

 through the rubber-stopper d, which admits by air-tight openings that and 

 another tube g h. The end / of the first tube does not penetrate far into 

 the vessel, but the second tube Ji g extends into the injection-fluid, while its 

 other end i is closed by the stop-cock h. When the stop-cock is open the 

 apparatus yields a continuous stream from 2^3 metres in height, which by 

 closing h may be reduced to a slow succession of drops. B stands upon 

 the support e, and is immersed in a water-bath w, which is heated by the 

 spirit-lamp t in the chamber s. 



For this apparatus the author claims the advantages that it is completely 

 under the control of the operator, whose hands are moreover left free ; it 

 may be used for all sorts of cold and warm injections, including chemical 



* The Microscope, vi. (1886) pp. 265-6 (1 fig.). 



t Stein, S. T., 'Das Licht,' 8vo, Hallo, 1884, pp. 307-10 (1 fig.). 



