186 PREPARATION AND MOUNTING 



however, the acetate of potash also is formed and as this 

 salt has an injurious action upon the cells, Dr. Goadby 

 recommends nitrate of lead to be used, which preserves 

 rather than destroys them. He also advises the addition 

 of two ounces of gelatine dissolved in eight ounces of water r 

 to eight ounces of the saturated solution of each salt ; but 

 with this addition the hot-water bath would be required to 

 keep the injecting fluid liquid. 



27. Many of these are best mounted in balsam, in the 

 same manner as those made in the ordinary way ; whilst 

 others are best shown when preserved in liquids, for which 

 purpose Goadby's fluid may be employed, 



28. This mode of making injections with chromate of lead 

 is deemed by many the best, especially where one colour 

 only is employed. But it must be allowed that there is a 

 little more danger of failure where two separate fluids are 

 used for the same vessels. 



29. We will now consider the best manner of making 

 transparent injections, which, for many purposes, possess an 

 undoubted advantage over opaque ones. But it must be 

 remembered that there are certain subjects to which no 

 transparent injection could be applied, as they are too thick 

 when in their natural state, and cutting would destroy all 

 that beauty which is shown by the different parts in their 

 relative adaptation. For those objects, however, which 

 must be cut into sections to display their wonders, or are 

 naturally thin such as some of the finer tissues, livers, 

 kidneys, &c., transparency is a great acquisition, and 

 enables us to understand the arrangement of the vessels 

 more perfectly. Again, another advantage is the simplicity 

 of the process; no hot water is needed with some pre- 

 parations, either for the subject or the injecting fluid, which 

 runs into the minute vessels thoroughly and easily, whilst 

 the cost is small. 



30. For this kind of injection no colour is so commonly 

 used as Prussian blue. It is not a good one, as was before 

 stated, for any opaque object, the light reflected from it 



