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 endless 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 removed with a camel-hair pencil and water. When dried it may be mounted in balsam, and having been injected with the transparent blue, its minute beauty is shown most perfectly. In injecting 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 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 disheartening. As I before stated, it is very difficult (if not impossible) to accomplish much without some knowledge of anatomy.