Experiments have been conducted on the production and treatment of motion sickness on human volunteers. Of 369 men tested after treatment by a placebo, 56.6% vomited. Tests were repeated at weekly intervals on 183 susceptible individuals so that 661 tests were performed. Repeat tests on 24 subjects not susceptible after treatment with a placebo showed that 12% were ill when no treatment was given. Ten susceptible subjects were swung through only one-half the usual degree of swinging. Of these eight vomited. This procedure selected persons of marked susceptibility to motion sickness.The consistency of the time of vomiting was determined by 106 tests on 65 susceptible men. In repeated tests after a placebo only eight were 13 min. more than the control test. For assaying drugs a standard procedure was adopted. Susceptible individuals were classed as those who, after taking a placebo, vomited before 30 min. of swinging. A susceptible individual was considered protected if in a test a week later he did not vomit and remained swinging for 13 min. longer than his control time. Improvement was present if a person vomited but the time was 13 min. longer than the control. In no case was swinging less than 30 min.The effect of a number of barbiturates on swing sickness has been determined. The most effective was V-12, ethyl-β-methylallylthiobarbituric acid, when administered in a divided dose of a total of five grains. In this case 78% were protected or improved. With a single dose of three grains 26% were similarly affected. V-17 (allylisoamylbarbituric acid)—two grains, V-16 (dicrotylbarbituric acid)—three grains, V-15 (allyl-sec-butylbarbituric acid)—one grain, V-14 (ethylcrotylthiobarbituric acid)—two grains, V-9 (n-butyl-1-methylallylthiobarbituric acid)—nine grains, and sodium amytal—one grain, showed less or no effect. Hyoscine hydrobromide in single doses of 0.4 and 0.65 mgm. showed 31 and 50% protected or improved respectively. The R.C.N. remedy gave a figure of 58%. After removal of nicotinic acid from the R.C.N. mixture 60% were benefited. Nicotinic acid alone, or pretreatment with thiamin gave no protection.A combination of three grains of V-12 with hyoscine was more effective than when either drug was used alone. With a dose of five grains of V-12 and hyoscine the results were only slightly better (80%) when compared with the same dose of V-12 alone (78%). It is suggested that the most effective form of administration of V-12 may be by divided doses of two and one-half grains twice daily for at least 24 hr. previous to exposure to motion.
PH metric method for the determination of nicotinic acid in plasma