OBSERVATIONS ON VARIOUS TYPES OF MOTION CAUSING VOMITING IN ANIMALS

Abstract

Extensive observations on the motion factors causing vomiting in animals are reported. Using a standard procedure of swinging, 81.5% of 70 dogs were found to be susceptible to motion. Cats were highly resistant to motion sickness and did not show an increased susceptibility after treatment with prostigmin.Susceptible dogs were divided into Groups 1, 2, and 3, of increasing susceptibility, by means of determining their response to swinging through angles of 90°, 45°, and . The percentages of animals found to be susceptible in these groups were 24, 40, and 36, respectively. Swinging the animal in a sideways position caused a reduction in the number being sick but the relative susceptibility of the three groups was unchanged.Exposure to the motion of a motor truck and a boat in rough weather caused 10 of 16 animals to be sick—seven being seasick. The dogs that vomited were not those most susceptible to swinging but were evenly distributed through the three groups.Animals have been exposed to the separate component motions of the swing and the effectiveness of the different motions compared. Horizontal motion is the most effective per se. The vertical component has some effect and the angular, probably none. No one component motion was as effective as the composite motion. The rate of the horizontal motion was an important factor per se, an increased effect being caused by an increased frequency. The effectiveness of vertical movement could be increased by increasing the distance traversed. Increasing the rate was ineffective.Swings with six different lengths of radii and swinging through three different angles are reported. The optimal length of radius appeared to be about 14 ft., longer or shorter radii causing a falling off in susceptibility. Reducing the angle of swinging caused a lower incidence of vomiting except where a very short radius was used. In this case an increased response occurred, probably related to the increase in rate of swinging.Attempts to obtain a more effective type of motion by using special apparatus are described. There was no evidence that these efforts improved the results obtained on the swing.