MICE THAT WALTZ

Evening Star, Issue 20468, 26 April 1930, Page 19

MICE THAT WALTZ

TO SAVE HUMAN LIVES Probably one of the strangest shows and no doubt among the funniest, that human beings hare witnessed for many a day recently was offered the staid scientists attached to the United States Bureau of Mines. First of all, two wee animals, looking for all the world like a cross between guinea pigs and common houso mice, were brought into the room in a small cage. Whereupon, to the delight of some of the scientists and the astonishment of others, the animals began a weird and crazy series of manoeuvres. Starting out with a sort of jerky scamper not unlike that of a fast-stepping comedy dancer, they came close to accomplishing a waltz step. But just as success seemed near, the animals performed in rapid succession a series of figure eights that -would have done credit to a fancy skater. They then began to pivot uncertainly on one foot, performing a good many gyroscopic circles without stopping. “ Arc these queer animals drunk, or am I? And if not, what’s going on here, anywhere? ” a visiting chemist asked of a colleague. With a smile the latter enlightened him; “You’ve been looking at what are known as Japanese waltzing mice. For some years they have been known in Asia, but until very recently their inane antics have been thought to be valueless so far as their being of any help to human beings is, concerned. “However, not so long ago, in connection with an exhibition of torpsicborean skill such as you’ve just been witnessing, the astonishing fact was discovered by the Bureau of Mines that these frolicsome creatures are really far more responsive to concentrations of the deadly carbon monoxide gas than are canaries, long used by the bureau during important mino rescue operations.” A Government expert went on to explain that the use of small animals, such as canaries and mice, for exploring and detecting atmospheres contaminated with carbon monoxide defends on the fact that, due to their nigh metabolic rate and oxygen demand, accompanied by high’ respiratory exchange and rate of circulation, they respond more quickly than man to a given concentration of the gas. From a practical viewpoint, this allows a margin of time between observable serious effects to the animal and serious effects to man, during which period man can return ijn safety to fresh air or else employ means of respiratory protection. It should be remembered, however, that during the time the animal is incurring a detectable degree of poisoning man is also absorbing some carbon monoxide, and in some cases be, may be seriously affected thereby, especially if the test animal is more tolerant than the average. The margin of time between effects in the animals and in man is not very wide, and experience with canaries has shown that an occasional bird may even be tolerant enough to fail to exhibit the looked-for symptoms before grave effects are noticeable in men.

It is also known that carbon-mon-oxide poisoning is augmented by considerable physical activity. This further, increases both .the demand for oxygen and the respiratory exchange and circulation of the blood. For this reason when using animals for detecting carbon monoxide, the bureau experts have endeavoured to k'#3p them as active as possible, and at the same time to minimise the activity on the part of the men, thereby tending to increase the sensitivity and widen the time between observable effects in birds and men. Numerous tests have been fairly successful when canaries have been used, hut in the case of ordinary house mice and white mice the animals tended to become more inactive and to huddle in the corners of their cage, thereby reducing their sensitivity. Having learned these important facts, the bureau scientists conceived the idea that perhaps, because of their incessant activity, Japanese waltzing mice might prove to be more susceptible to carbon monoxide than either canaries or common mice. This reasoning was borne out by comparative tests. In fact, the wee waltzers showed signs of response to the ‘ deadly fumes considerably in advance of their rivals. The signs were first manifested in a weakness of the hind limbs and by the animals showing a tendency to fall while performing their characteristic dances; later all their movements were slowed down, and still later an almost complete inability to perform the movements. However, the recovery of the animals after their exposure to the dangerous fumes was rapid. Apart from their new-found importance, the waltzers are of interest to the student of strange animals. A major reason is that a mystery has long surrounded them. Particularly is there a veil of uncertainty concerning their earliest history. Even the distinguished professor Robert M. Yerkes, of Harvard, who has personally made the closest kind cf investigation of the dancers, having bvM a great many of them and tested almost countless others, is forced to admit that he has found no mention of them in scientific literature prior to the year 1890. There are a variety of interesting descriptions of their weird dance by men who lay some claim to knowledge of the dancers intimate habits. One expert, for instance, says: “The dance, if such it be called, generally seizes the mouse when it emerges from its darkened sleeping place, and this would lead one to believe that the light conveys an impression of shock to the brain through the eyes, thereby disturbing the diseased centres and giving impetus to the giddy gyrations.” But Dr Yerkes pooh-poohs this belief, pointing out that his extensive tests have proved to his satisfaction that the mice have a regular period of greatest activity contingent only upon the time element, and that is between tho hours of 5 and 10 p.m. He further explains: The most striking features of the ordinary behaviour of the dances are restlessness and movement in circles. Even before it is old enough to escape from the nest it begins to movein circles and to exhibit the quick, jerky head movements which are characteristic of the race.” Just as the stage and screen have their widely divergent types of dancing stars, so do the members of this queer animal family. There are three main types of dancing mice—those which twirl almost uniformly toward the right, those which cavort to the left, and those which manoeuvre about as frequently in one direction as another.