The essentials of healthA text-book of anatomy, physiology, hygiene, alcohol, and narcotics . n, but is thrown into a number of ridges or convo-lutions. The number of convolutions and the depth towhich they reach vary in the different animals. In some,the surface is perfectly smooth, as in the pigeon and fpog;in others, the convolutions are shallow and few in num-ber ; but in man, they are many and very deep. As a rule, THE NERVOUS SYSTEM. 261 the more intelligent the animal so much the more numer-ous and so much the deeper will be the convolutions ofthe cerebrum. The reasonfor this is readily
The essentials of healthA text-book of anatomy, physiology, hygiene, alcohol, and narcotics . n, but is thrown into a number of ridges or convo-lutions. The number of convolutions and the depth towhich they reach vary in the different animals. In some,the surface is perfectly smooth, as in the pigeon and fpog;in others, the convolutions are shallow and few in num-ber ; but in man, they are many and very deep. As a rule, THE NERVOUS SYSTEM. 261 the more intelligent the animal so much the more numer-ous and so much the deeper will be the convolutions ofthe cerebrum. The reasonfor this is readily under-stood when the structureof the brain is made and White Matter ofthe Cerebrum. The graymatter is on the outside ofthe brain: the white mat-ter is within, forming thecenter of the brain. Thewhite matter is raised inslight folds on its surfaceto form the center of theconvolutions ; but the bulkof the convolutions is formed by the gray matter. It has been stated thatthe gray matter consists principally of nerve cells, andthat these cells are the active agents in originating,. Fig. 94. (1) the brain of a pigeon ;(2) the brain of a frog,— both viewedfrom above. There are no convolu-tions on the cerebrum, h.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectphysiology, bookyear1
