ETC. 703 



until the syringe has been nearly emptied, when the stop-cock 

 must be turned off, and the syringe refilled with warm injection 

 as before. 



" Care must always be taken to keep the syringe in the inclined 

 position, so that any air which may be in it, may remain in the 

 upper part ; and for the same reason, all the injection should not 

 be forced out, for fear of the enclosed air entering the vessels, in 

 which case all chance of obtaining a successful injection would 

 be destroyed. 



" After a certain quantity of fluid has been injected, it will be 

 necessary to use a greater amount of force, w r hich, however, must 

 be increased very gradually, and should only be sufficient to de- 

 press the piston very slowly. If too great force be employed, 

 extravasation will be produced before the capillaries are half 

 filled. Gentle and very gradually-increased pressure, kept up 

 for a considerable time, will cause the minute vessels to become 

 slowly distended without giving way to any great extent. At 

 the same time it must be borne in mind that extravasation fre- 

 quently occurs at various points in a successful injection ; but the 

 longer this event can be kept off, the more likely are we to 

 succeed. 



"When the injection begins to flow from the large veins 

 mixed with the blood contained in these vessels, and the surface 

 of the injected preparation looks of a red color, and has a some- 

 what velvety appearance, we may infer that the injection has 

 been completed. This occurs at different periods. Sometimes 

 the first or second syringeful causes a general redness of surface, 

 while in other instances a considerable time will elapse before 

 more than a slight blush appears. As a general rule, it is better 

 to proceed slow r ly and cautiously, and to use as little force as pos- 

 sible, which should not be more than sufficient to produce an 

 observable depression on the piston. Many minute injections 

 will require an hour or more to complete. 



" When the injecting is completed, and all the openings by 

 which any of the injection could escape during cooling are closed, 

 the preparation should be placed in cold water, and allowed to 

 remain until the size has set, which will require twelve hours or 

 more in hot weather." 



In the Medical Examiner of Philadelphia, for December, 1849, 

 Dr. P. B. Goddard details the following method of making 

 minute ethereal injections, originally employed by him. 



"For the purpose of making such an injection, the anatomist 

 must provide himself with a small and good syringe ; some ver- 

 milion, very finely ground in oil ; a glass-stoppered bottle, and some 

 sulphuric ether. The prepared vermilion paint must be put into 

 the ground-stoppered bottle, and about twenty or thirty times its 

 bulk of sulphuric acid added ; the stopper must then be put in 

 its place, and the whole well shaken. This forms the material 

 of the injection. Let the anatomist now procure the organ to be 



