"Lectures on Animal Chemistry." By Dr. Bence Jones. Medical Times, Sept. 13th, 1851. See also Prin. of Phys., p. 171.
Cyclopædia of Anatomy and Physiology, Vol. IV, p. 506.
From a remark of Drs. Wagner and Leuckart this chemical evidence seems to have already suggested the idea that the sperm-cell becomes "metamorphosed into the central parts of the nervous system." But though they reject this assumption, and though the experiments of Mr. Newport clearly render it untenable, yet none of the facts latterly brought to light conflict with the hypothesis that the sperm-cell contains unorganized co-ordinating matter.
Quain's Elements of Anatomy, p. 672.
The maximum weight of the horse's brain is 1 lb. 7 ozs.; the human brain weighs 3 lbs., and occasionally as much as 4 lbs.; the brain of a whale, 75 feet long, weighed 5 lbs. 5 ozs.; and the elephant's brain reaches from 8 lbs. to 10 lbs. Of the whale's fertility we know nothing; but the elephant's quite agrees with the hypothesis. The elephant does not attain its full size until it is thirty years old, from which we may infer that it arrives at a reproductive age later than man does; its period of gestation is two years, and it produces one at a birth. Evidently, therefore, it is much less prolific than man. See Müller's Physiology (Baly's translation), p. 815, and Quain's Elements of Anatomy, p. 671.