# Page:Popular Science Monthly Volume 4.djvu/610

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THE POPULAR SCIENCE MONTHLY.

the smallest proportion, either to its own concomitant structures, or to the rest of the body. The actual weight of a common codfish was 14,875 grains; the brain weighed only 9½ grains; thus making the ratio of 1 to 1,565. In man, the average weight of the brain is about 3 pounds, the medium weight of the body 150 pounds, making a ratio of 1 to 50. The above is a correct statement of the relative weight of the brain to the body of the lowest of the type, the fish, and the highest, man; showing the ratio of the weight of the brain in man, to that of the body, to be over 31 times greater than the same ratio in the fish. But, if we estimate the proportionate weight of merely the cerebral hemispheres, or the instruments of thought, to that of the body in the fish and man, we obtain a difference of 124, which expresses the number of times the cerebral hemispheres of man are greater than those of the fish; in other words, if the body of a fish and that of man were of equal weight, the cerebral hemispheres of the latter would weigh 124 times more than those of the former. Further, the relative weight of the cerebral hemispheres, as we ascend from the fish through the vertebrate sub-kingdom of animals, will be found to correspond to the variation of the face-line from a parallel with the dorsal surface.

To recapitulate: 1. The size and weight of the brain will be found to increase with the angle of the face to the axis of the body. 2. The expansion of the brain-case, with a proportionate diminution of the facial bones, is an invariable accompaniment of an increased facial angle throughout the vertebrate sub-kingdom of animals. 3. The mental manifestation and power have a direct relation to the angle above indicated. 4. The position assumed by the body of the animal in its change from the horizontal to the perpendicular attitude, also very generally agrees with the facial angle of its subject. 5. The projection of the jaws, in front of the ocular orbits, is also a correlative index to the above data. 6. The relative ascendency of the two factors, the physical and mental, with their numerous phenomena, is an index to all of the above relations, and shows very conclusively the gradual turning from the lowest instincts of the brute to the most complex mental powers of man.