Page:The third Huxley lecture.pdf/40

36 a fine sewing needle I passed a delicate thread of silk through the superficial layers of the left cornea, and cut the ends off close with scissors. Next day the eye was much inflamed and its condition was aggravated on the day following, while the other eye remained healthy. As I have already said, the rabbit was killed on the expiry of 48 hours. This having been done by pithing, I at once divided the blood-vessels in the neck while the heart was still beating, so as to allow all blood that was free to flow to escape from the head. I then removed the two eyes and cut them both across transversely midway between the cornea and the optic nerve, and compared the inflamed eye with the healthy. I will not detain you with a description of the anterior halves of the globes, though they were very interesting, but will at once speak of their posterior portions, more remote from the part where the exciting cause had been in operation on the left side. In that eye the retina was much more readily detached than in the right, and showed small spots of ecchymosis, while the blood vessels were more conspicuous. The two choroids presented a striking contrast; "the vessel in the right eye" (to quote my notes again) "being not at all conspicuous, while in the left eye the membrane was scarlet; and this depended not merely upon fulness of the vessels but upon darker tint of their contents in consequence of excess of red corpuscles."

It is matter for discussion how inflammatory congestion is brought about by nervous action. It