190 PREPARATION AND MOUNTING 



the liquid should be forced into it until a slight paring o\ 

 the hoof shows the colour in the fine channels there. 

 Perhaps one of the most beautiful and interesting objects is 

 the skin or section of a cat's tongue. On examination we 

 shall readily learn the reason why we feel such a roughness 

 when we allow the cat to apply her tongue to our hands. 

 In appearance we shall be almost ready to say that there is 

 no little resemblance in the arrangement betwixt this tongue 

 and those of the molluscs already described. The liver of a 

 rabbit or any other animal is an easy and beautiful object 

 for injection. Sections made with Valentin's knife, and 

 mounted in balsam, are not at all difficult, and worth double 

 the time they occupy. 



35. When the lungs of small animals are injected, the 

 finest fluid must be used, as some of the capillaries are so 

 small that it is not an easy matter to fill them properly. 

 And before entering upon these subjects, a certain pro- 

 ficiency in the mode of using the syringe, &c., should be 

 obtained by practising upon simpler parts. 



36. No subjects are more difficult to inject than fish, 

 owing to the extreme softness of their tissues. Mr. Hogg 

 recommends the tail of the fish to be cut off, and the pipe 

 to be put into the divided vessel which lies just beneath the 

 spinal column ; by which method beautiful injections may 

 be made. The gills, however, are the most interesting part 

 as microscopic objects. 



37. These instructions may seem very imperfect to those 

 who have had much experience in this branch ; but they 

 will remember that their own knowledge was not gained 

 from any written descriptions, but was forced upon them 

 by frequent failures, some of which probably were very dis- 

 heartening. As I before stated, it is very difficult (if not 

 impossible) to accomplish much without some knowledge of 

 anatomy. 



38. I may here mention that the transparent injections 

 sent over from the Continent are beautifully executed by 

 Hyrtl of Vienna (who states that the injected fluid is com- 



