128 PREPARATION AND MOUNTING 



use of a higher power in their examination, and preserving them 

 in a more natural form. 



34. A few subjects may be noticed which are very beautiful 

 when injected, and amongst these are the eyes of many animals. 

 They must be injected by the artery in the back part, and when 

 the blue transparent liquid is employed, nothing can exceed the 

 delicate beauty which some of the membrane bears. It must, 

 however, be dissected with care, but well repays us for the 

 trouble. Water-newts and frogs are not difficult subjects, and in 

 their skin and other parts are many interesting objects. Amongst 

 the commoner animals rats, rabbits, cats, &c. &c. almost end- 

 less employment may be found, making use either of portions or 

 the whole animal at once. The intestines of many of these are 

 very beautiful. We must divide them with a pair of scissors 

 along the tube, and cleanse them from all the matter ; the coating 

 may then be laid upon a slide and any remaining impurity re- 

 moved with a camel-hair pencil and water. When dried it may 

 be mounted in balsam, and having been injected with the trans- 

 parent blue, its minute beauty is shown most perfectly. In in- 

 jecting a sheep's foot, which is a good object, the liquid should 

 be forced into it until a slight paring of the hoof shows the colour 

 in the fine channels there. 



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 proficiency 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. Dr. 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 remem- 

 ber 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 disheartening. As I before stated, 



