136 OF FOOD, AND THE DIGESTIVE PROCESS. 



bile is usually increased. The interesting observation was made by Ruble, 

 tbat if a manometer be fastened into the stomach, and vomiting be excited, 

 instead of an elevation there is a descent of the mercury, momentarily pre- 

 ceding the expulsion of the contents ; this must doubtless be referred to the 

 sudden and active opening of the cardiac orifice produced by the dilatator 

 fibres described by Schitf, which occurs just antecedently to the pressure ex- 

 erted by the muscles of the abdomen. There can be but little doubt that 

 the violent but fruitless efforts at vomiting which we occasionally witness 

 (two or three such efforts frequently preceding the effectual one), are pre- 

 vented from emptying the stomach by the obstinacy with which the cardiac 

 sphincter is kept closed ; just as the expiratory effort which assists in empty- 

 ing the stomach, is prevented, by the firmness with which the glottis is held 

 shut, from expelling the contents from the chest. The immediate causes of 

 vomiting may be reduced to several different categories. 1st. The contact 

 of irritating substances with the mucous membrane of the stomach itself; 

 these, however, cannot act by direct stimulation upon more than its own 

 muscular coat ; and their operation upon the associated muscles must take 

 place by reflexion, through the "nervous circle" furnished by the pneumo- 

 gastrics and the motor nerves of expiration. 2d. Irritations applied to other 

 parts of the body, likewise operating by simply reflex transmission ; as in the 

 vomiting which is consequent upon the strangulation of a hernia, or the 

 passage of a renal calculus. 3d. To the direct irritation of the nervous 

 centres by certain irritants (Tartar Emetic, Apomorphine); and perhaps we 

 may add, the vomiting that occurs after division of both pneumogastrics 

 the division of one having but little effect. 1 4th. Impressions received 

 through the sensorial centres, which may be either sensational or emotional, 

 but which do not operate unless they are felt. In this mode seems to be ex- 

 cited the vomiting that is induced by tickling the fauces, which first gives 

 rise to the sensation of nausea ; as well as the vomiting consequent upon 

 disgusting sights, odors, or tastes, and upon those peculiar internal sensa- 

 tions which are preliminary to "sea-sickness." The recollection of these 



1 This appears to be demonstrated by the experiments of Chouppe (Societe de Rio- 

 logie, Seance, 18tb July, 1874), who observed that after section of both pneumogas- 

 trics in dogs, the intravenous injection of tartar emetic and of npomorphine caused 

 free vomiting, whilst Ipecacuanha or its active principle, Emetine, had no action; 

 from whence the conclusion may be drawn that the two first-named drugs act on the 

 vagal centre as well as upon the pcripheric extremities of the vagi in the gastric 

 mucous membrane, whil.-t the action of emetine seems to be confined to the latter. 

 Hermann (Pfluger's Archiv, Band v, 1872, p. 280) grounding his opinion on the 

 result of an experiment made by Grimm (Idem, Band iv, 1871, p. '-20.")), showing that 

 tartar emetic injected into the veins takes a longer time to act than when injected 

 into the stomach, believes that this salt has a specific action on the parietes of the 

 .stomach ; but it may be remarked that, as above stated, Magendie long ago showed 

 that efforts to vomit followed the injection of tartar emetic, after the ablation of the 

 entire stomach. (See D'Ornellas's Bulletin General" de Therapeutiquc, 187'">, p. I'.'M 

 ct set].) D'Ornellns considers that vomiting may be produced by three kinds of 

 ett'ori> : 1. Intrinsic, or by the contraction of the stomach alone; 2, Extrinsic, or 

 by the contraction of the expiratory muscles; and 8, by mixed or combined and co- 

 ordinated, intrinsic and extrinsic efforts j and the nerves implicated mav l>e either 

 the pneumogastr'ics, the nerves of special sense, or the sympathetic. In meningitis, 

 in ca>rs of cerebral tumor, and in hu-morrhage, the feeling of nausea is probably 

 Conveyed by the sensory branches of the glosso-pharyngeal nerve. The nauseating 

 principle ol' some drugs, though generally, is not always identical with that produc- 

 ing their emetic etVcct. Thus in the case of Ipecacuanha the nauseating principle is 

 an odorous substance, capable of separation by ether, in which it is soluble, whilst 

 the emetic principle is soluble in alcohol. The former can produce vomiting im- 

 mediately on being swallowed, or even before by its action on the olfactory and 

 glosso-phary ngeal nerves, whilst the latter acts as above stated on the vagal branches 

 distributed to the stomach. 



