Evolution; its nature, its evidences, and its relation to religious thought . Fio. 52.—Fish-stage, of, olfactive lobe; cr, cerebrum ; th^ thalamua;o/, optic lobe ; c6, cerebellum ; m, medulla. taxonomic series, are passed through as transient stages inthe embryonic development of the human brain, and inthe order given above. The very early condition of thehuman brain is represented in Fig. 51. It is evidently. Fig. 53.—Reptile-stage. nothing more than the intercranial continuation of thespinal cord, enlarged a little into three swellings or gan-glia. These are the early representatives of the
Evolution; its nature, its evidences, and its relation to religious thought . Fio. 52.—Fish-stage, of, olfactive lobe; cr, cerebrum ; th^ thalamua;o/, optic lobe ; c6, cerebellum ; m, medulla. taxonomic series, are passed through as transient stages inthe embryonic development of the human brain, and inthe order given above. The very early condition of thehuman brain is represented in Fig. 51. It is evidently. Fig. 53.—Reptile-stage. nothing more than the intercranial continuation of thespinal cord, enlarged a little into three swellings or gan-glia. These are the early representatives of the medul-la, the optic lobes, and the thalamus ; which last maybe regarded as the basal and most fundamental part ofthe cerebrum. This stage may be regarded as lowerthan that of the ordinary fish. I have called it, therefore,the sub-fish stage. The cerebellum is a subsequent out-growth from the medulla, as is the cerebrum and olfac- 106 EVIDENCES OF THE TRUTH OF EVOLUTION. tive lobes from the thalamus. Fig. 52 may be said, there-fore, to represent fairly the fish-stage. Henceforward theprincipal growth is in the cerebrum and cerebellum,both of which are subsequent outgrowths of the origi-nal simple ganglia, the medulla, and the thalamus. Thecerebrum especially increases steadily in relative size, firstbecoming larger than but not covering the optic lobes(Fig. 53). This represents the reptilian stage. Ne
Size: 2337px × 1069px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjectreligion, bookyear192
