722 OF REPRODUCTION. 



completion of these changes; and various malformations, involving an imper- 

 fect discharge of the function, may hence result.* 



945. The Alimentary Canal has been shown to have its origin in the Yolk- 

 sac or Umbilical Vesicle ; being a portion pinched off (as it were) from that 

 part of it, which is just beneath the Spinal Column of the Embryo ( 937). 

 At first it is merely a long narrow tube, nearly straight, and communicating 

 with the Umbilical Vesicle at about the middle of its length ; thus it may be 

 regarded as composed of the union of two, an upper and a lower division. 

 At first, neither Mouth nor Anns exists ; but these are formed early in the 

 second month, if not before. The tube gradually manifests a distinction into 

 its special parts, (Esophagus, Stomach, Small Intestine, and Large Intestine ; 

 and the first change in its position occurs in the Stomach, which, from being 

 disposed in the line of the body, takes an oblique direction. The curves of 

 the large and small intestines present themselves at a later period. It is at the 

 lower part of the small Intestine, near its termination in the large, that the 

 entrance of the Omphalo-Enteric duct exists ; and a remnant of this canal is 

 not unfrequently preserved throughout life, in the form of a small pouch or 

 diverticulum from that part of the intestine. The various Glandular structures 

 connected with the alimentary canal, originate in diverticula from its walls, in 

 the manner already described in regard to the Liver ( 826, g}. The Lungs 

 and Respiratory apparatus a*re formed in like manner, as diverticula from the 

 (Esophagus ( 757, b, c). 



946, The mode in which the chief organs of the Human embryo originate 

 having been thus described, and sufficient particulars in regard to their subse- 

 quent development having been already given under distinct heads, it is un- 

 necessary here to add more on this very interesting but complex subject; be- 

 cause for practical purposes there is little or no advantage to be gained from 

 the most perfect aquaintance with it. The most important of all the facts that 

 have come under our review, is that which has been stated as in the highest 

 degree probable, if not yet absolutely proved, in regard to the relative offices 

 of the Male and Female in this hitherto mysterious process. According to 

 the view here given, the Male furnishes the germ; and the Female supplies 

 it with Nutriment, during the whole period of its early development. There 

 is no difficulty in reconciling such a doctrine with the well-known fact, that 

 the offspring commonly bears a resemblance to both parents (of which the 

 production of a hybrid between distinct species is the most striking example) ; 

 since numerous phenomena prove that, in this earliest and simplest condition 

 of the organism, the form it will ultimately assume very much depends upon 

 circumstances external to it ; among which circumstances, the kind of nutri- 

 ment supplied will be one of the most important.t Upon the same principle 

 we may account for the influence of the mental condition of the Mother upon 

 her Offspring^ during a later period of pregnancy. That such influence may 

 occur, there can be no reasonable doubt. " We have demonstrative evidence," 

 says Dr. A. Combe,J " that a fit of passion in a nurse vitiates the quality of 

 the milk to such a degree, as to cause colic and indigestion [or even death] 

 in the suckling infant. If, in the child already born, and in so far independent 

 of its parent, the relation between the two is thus strong, is it unreasonable to 

 suppose that it should be yet stronger, when the infant lies in its mother's 

 womb, is nourished indirectly by its mother's blood, and is, to all intents and 

 purposes, a part of her own body? If a sudden and powerful emotion of her 

 own mind exerts such an influence upon her stomach as to excite immediate 



* See Principles of General and Comparative Physiology, Chap. vi. 

 f Sec Principles <il' (Icnenil and Comparative Physiology, (305. 

 j On the Management of Infancy, p. 7G. 



