822 



INDEX. 



Vena portae, its arrangement, 101, 



3!7- 



Venous blood, characters of, 85-9. 

 Ventilation, necessity of, 214. 

 Ventricle, fourth, of brain, 5 1 1, 53 1. 

 Ventricles of heart, 102. 

 capacity of, 128. 

 contraction of, no. 



effect on arteries, 144, 149 . 

 on circulation, 132. 

 on veins, 1 70. 

 force of, 126. 

 development of, 766. 

 dilatation of, 112. 

 of larynx, office of, 619. 

 Ventriloquism, 694. 

 mechanism of, ib. 

 Vermicular movement of intes- 

 tines, 345. 



Vermiform process, 524. 

 Vertebrae, development of, 744, 759. 

 Vesicle, germinal, 720. 

 Graafian, 715, 718. 



bursting of, 723-25. 

 umbilical, 745. 



Vesicles of vascular glands, 411. 

 Vesicula, germinativa, 720. 

 Vesiculae seminales, 735. 

 functions of, 736. 

 reflex movements of, 505. 

 Vesicular nervous substance, 473. 

 Vestibule of the ear, 676. 



of vagina, 717. 



Vibrations, conveyance of, to au- 

 ditory nerve, 683. 

 perception of, 627. 

 of vocal cords, 617. 

 Vidian nerve, 550. 

 Villi of intestines, 306. 

 action in digestion, 338. 

 on intestinal glands, 301. 

 Villi of chorion, 751. 



in placenta, 756. 

 Visceral arches, development of, 



761. 

 cavities, serous membranes of, 



396. 



laminfe, 745, 761. 

 layer of pleura, 188, note. 

 Vision, 636. 

 angle of, 655. 



at different distances, adapta- 

 tion of eye to, 649-51. 

 contrasted with touch, 656. 



Vision, continued. 



corpora quadrigemina the prin- 

 cipal nerve-centres of, 521. 

 correction of aberration, 648, 



649. 



of inversion, 653. 

 direction of, 656. 

 direction of rays in, how regu- 

 lated, 642. 



distinctness of, how secured, 646. 

 double, 666. 



duration of sensation in, 659. 

 estimation of the form of ob- 

 jects, 656. 



of their motion, 657. 

 of their size, 654. 

 field of, size of, ib. 

 focal distance of, 649. 

 impaired by lesion of fifth 



nerve, 546, 547. 

 influence of attention on, 658. 

 modified by different parts of 



the retina, 662. 

 organ of, 636. See Eye. 

 phenomena of, 644. 

 in quadrupeds, 667. 

 single, with two eyes, 664. 



its cause, 667-71. 

 structures essential for, 645. 

 Visual direction, 656. 

 Vital capacity of chest, 202. 



motions, 578. 

 Vitality. See Life. 

 Vitelline duct, 745. 

 membrane, 719, 740. 

 spheres, 740. 



Vitellus, or yelk, 720. See Yelk. 

 Vitreous humour, 644. 

 Vocal cords, 



action of in respiration, 200,222. 

 approximation of, effect on 



height of note, 612. 

 attachment of, 608. 

 elastic tissue in, 37. 

 longer in males than in females, 



615. 



position of, how modified, 610. 

 vibrations of, cause voice, 604, 



618. 



Voice, 604. 

 of boys, 615. 

 compass of, 614. 

 conditions on which strength 

 depends, 618. 



