The history of creation, or, The development of the earth and its inhabitants by the action of natural causes : a popular exposition of the doctrine of evolution in general, and of that of Darwin, Goethe and Lamarck in particular . animals possess-ing skull and brain, the brain, which is at first only thebladder-shaped dilatation of the anterior end of the spinalmarrow, divides into five bladders lying one behind theother, four superficial, transverse in-nippings being five hrain-bladders, out of which afterwards arise allthe different parts of the intricately constructed brain, c
The history of creation, or, The development of the earth and its inhabitants by the action of natural causes : a popular exposition of the doctrine of evolution in general, and of that of Darwin, Goethe and Lamarck in particular . animals possess-ing skull and brain, the brain, which is at first only thebladder-shaped dilatation of the anterior end of the spinalmarrow, divides into five bladders lying one behind theother, four superficial, transverse in-nippings being five hrain-bladders, out of which afterwards arise allthe different parts of the intricately constructed brain, canbe seen in their original condition in the embryo representedin Fig. 7. It is just the same whether we examine the em-bryo of a dog, a fowl, a lizard, or any other higher vertebrateanimal. For the embryos of the different skulled animals(at least the three higher classes of them, the reptiles, birdsand mammals) cannot be in any way distinguished at thestage represented in Fig. 7. The whole form of the body isas yet exceedingly simple, being merely a thin, leaf-like , legs, intestines, etc., are as yet completely the five bladders are already quite distinct from oneanother. 04 THE HISTORY OF Fig. 7.—Embryo of a mammal or bird, inwhich the live brain-bladders have just com«menced to develop, v. Fore brain, z. Twixt braiium. Mid brain, h. Hind brain, n. After brain,p. Spinal-marrow, a. Eye-bladders. w. Primi-tive vertebrse. d. Spinal-axis or notochord. The first bladder, the fore brain (a),is in so far the most important thatit principally forms the hemispheres ofthe so-called larger brain (cerebrum),that part which is the seat of thehigher mental activities. The morethese activities are developed in theseries of vertebrate animals, the moredo the two lateral halves of the forebrain, or the hemispheres, grow at theexpense of the other bladders, andoverlap them in front and from above. In man, where theyare most strongly developed, agreeing with
Size: 983px × 2544px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlankestererayedwinray, bookcentury1800, bookdecade1880
