VOMITION. 
557 
1st. A greater frequency of the occurrence of the phe¬ 
nomenon than is generally supposed; and, 2dly, disorder or 
disease of the stomach in connection therewith. 
Strange as it may seem, this is borne out by the very thing 
Mr. Gamgee has adduced against it, viz., sea-sickness. The 
primary cause of this unpleasant state I presume to be 
indefiniteness of motion, i. e. } a motion unusual to the 
muscles and the department of the nervous system ruling 
them. In the case of a swing, the tendency to sickness is 
produced by the centrifugal force withdrawing or checking 
the supply of blood to the head. In swimming, cramp is a 
result of a strange or unusual action of the muscles, and 
not of the cold. As the tendency to cramp becomes less 
with the increased frequency of the exercise, so the tendency 
to sea-sickness, and a kind of cramp producing vomition, 
decrease on becoming accustomed to the motion of a vessel. 
On land (the result of constant practice) a definite com¬ 
mission by the nervous system, or the will to the muscles, is 
followed by a definite result, viz., progression, retrogression, 
&c.; but on board a rolling ship, the will is able to produce 
no definite motion at all,—hence irritation and then sea¬ 
sickness. All is vague. 
Some pschychologists have attributed it to a sense of 
insecurity; but most sea-sick people are so when they feel 
themselves perfectly secure. The state of the stomach at 
the time plays a considerable part in the induction of the 
sickness. That a state of repletion tends rapidly to induce 
it, I have frequently witnessed; and immunity from it, the 
result of the opposite state, I have as often experienced in 
my own person, and seen the exemption in others. To 
enlarge, it is quite in a passenger’s option whether he be sick 
or not. The conditions to be fulfilled to secure immunity 
are, a hot stimulant, eschewing all attempts to think or speak, 
and going to bed, and thence to sleep. 
Mr. Gamgee considers the fact of vomition occurring or 
continuing when or after the stomach is empty, as proof of a 
nervous cause alone. He overlooks the fact of there being a 
copious excretion of very acid gastric juice, and therefore very 
irritating. Under the circumstances, the wonder would be 
that vomition did not occur. 
I have not the details of M. Magendie’s experiment; but 
if he first produced nausea through the agency of the clocfs 
stomach, and then substituted a piefs , the experiment to me 
appears inconclusive. The first step in such an experiment 
ought to be, the change of the stomachs. Vomition some¬ 
times occurs in the human subject through sympathy; but it 
