678 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Heat tho solution containing the carmine and that containing the acid 

 to the same degree, by placing the bottles containing them in a pan of 

 water kept hot on a stove or over a lamp. Add gradually with constant 

 stiirin" the gelatin solution containing the acid to that containing the 

 carmine. Filter while hot through two thicknesses of flannel. The fluid 

 can be poured into the flannel shaped into a bag, when pressure on the 

 sides of tho bag will cause the contained fluid to pass through the cloth. 

 Adil four dr. of chloral hydrate and shake until dissolved. The chloral 

 will preserve the mass for quite a long time, but if it is to be used within 

 a day or two the chloral is not necessary. A mass made up by the 

 formula given is sufficient in amount to inject a cat or rabbit. If 

 needed for a single organ the ingredients can be reduced to the relative 

 proportion. 



A manometer should always be used for injecting and the apparatus 

 suggested by the author consists of a wide-mouthed bottle fitted with 

 a manometer made from a piece of bent glass tubing fastened to an 

 upright board with a scale in inches or millimetres marked on it. The 

 only other articles necessary are a tin box with a shelf inside on which 

 to lay the animal to be injected ; a sheet of glass large enough to cover 

 the box, a thermometer, a few feet of rubber and glass tubing, and a 

 couple of spring clamps for closing the tubing when it is necessary to 

 stop the flow. Good atomizer bulbs are also required. There is no 

 difficulty in maintaining a pressure of 100 mm. while injecting. 



Before making an injection the apparatus should be tested by closing 

 the exit tube and gradually raising the pressure to 100 mm., in order 

 that any defects may be remedied. Before killing the animal the 

 box is filled below the shelf with water at 40° C, and a lamp placed 

 underneath to keep the temperature at that point. The melted injecting 

 mass is then poured into the injecting bottle in order that it may attain 

 the same temperature. About 12 oz. of a 3/4 per cent, salt solution 

 is poured into another bottle also arranged with injection-tubes and 

 placed in the box. The animal is chloroformed, and the apex of the 

 heart having been snipped oif, the salt solution is injected at a pressure 

 of 50 mm. until it runs clear. The carmine mass is then injected, begin- 

 ning with a pressure of .50 mm., and gradually increased to 100 mm. 

 When the injection is finished the animal is cooled down in ice- water or 

 a refrigerator, and the selected parts afterwards hardened in spirit. 



Eobin's, Lacaze-Duthiers', and Farahceuf's Injecting Syringes,* — 

 Dr. Beale f prefers the syringe to any of the contrivances described in 

 this Journal, 1884, pp. 643-51, for producing pressure by the fall of a 

 liquid. The ordinary syringe has, however, several inconveniences 

 which it is the object of the following modified forms to remedy. 



Eobin's syringe (fig. 113), has a rack-and-pinion movement to the 

 piston so as to avoid the dangerous irregularities of pressure which are 

 very liable to occur, especially after prolonged work. It also has a 

 second tube and tap at the side for taking up the injecting fluid. 



* Fol's Lehrbuch der Vergl. Mikr. Anatomic, 1884, pp. 21-4 (3 figs.). 



t " After having tried many different methoda of proceeding, I find that npon 

 the whole the ordinary injecting syringe is the most successful as well as tho 

 cheapest, the most convenient, and the most simple instrument, and it is very easily 

 kept in good order. It need scarcely be said that by no mechanical means can such 

 varieties of pressure be obtained as by tlie aid of the muscles of the fingers and 

 thumb, while the pressure can be instantly modified or removed at the pleasure of 

 the operator." — ' How to work with the Microscope,' 1880, p. 104. 



