DIGESTION 203 



(5) muscular loops encircling the cardia, the contraction of 

 which keeps the opening tightly closed ; (6) the stomach not 

 being in contact with the abdominal wall. All these and other 

 reasons have been assigned as the cause of non-vomiting in 

 the horse. Yet on turning to ruminants, which also normally 

 do not vomit, we find the stomach, gastric compartments, and 

 oesophagus freely communicating, the largest reservoir lying in 

 contact with the abdominal wall, the cardia freely open, the 

 oesophagus of great size, and, still stranger, the animal possessing 

 the ability, under the control of the will, to bring up food from 

 the stomach as a normal condition, and yet unable to vomit ! 

 It is evident, therefore, that all these theories are not sufficiently 

 satisfactory to account for the absence of vomiting, and we are 

 bound to suppose that the vomiting centres in the medulla of 

 both horse and ox are either only rudimentary or very insensi- 

 tive to ordinary impressions. 



Vomition in the horse is no doubt seriously interfered with by 

 the thickened oesophagus, contracted cardia, and the arrange- 

 ment of the muscular fibres. The folds of mucous membrane 

 filling up the orifice could offer no serious obstruction to a 

 distended stomach, for it is known that even when this mem- 

 brane is dissected away post mortem, a stomach will burst 

 rather than allow fluid or air pumped in at the pylorus to escape 

 at the cardia, unless the muscular fibres surrounding it be partly 

 divided. Vomition in the horse is generally indicative of rup- 

 tured stomach, and much has been written as to whether vomit- 

 ing occurs before or after rupture. From no inconsiderable 

 experience of these cases, the writer has arrived at the con- 

 clusion that it may occur at either time, and that a horse may 

 vomit though a rent 7 or 8 inches long exists in the stomach wall. 



Dilatation of the cardia and oesophagus is essential to the 

 act of vomition in the horse, and in all cases where vomiting 

 occurs during life the cardia is so dilated that two or three 

 fingers may readily be introduced into it. It is perfectly possible 

 for a horse to vomit and recover (showing that it had not a 

 ruptured stomach), and it is not unusual to have attempts at 

 or actual vomition when the small or large intestines are twisted. 

 Vomiting in the horse is not as a rule attended by any distressing 

 symptoms ; the ingesta dribble away from one or both nostrils ; 

 occasionally an effort is made on the part of the patient, the 

 head being depressed to facilitate expulsion, but more than this 

 is very rarely seen.* 



* The only case of vomiting the writer has seen in the horse which resem- 

 bled that presented by the human subject was in a case of volvulus of the 

 small bowels. The horse was lying on his chest with the nose extended, 

 the ingesta gushed in a stream from both nostrils, and a sound accompanied 

 the effort. 



