J.D.B. News Letter

(By our Denver correspondent)

A new method of detecting tuberculosis has been evolved by the research department of the National Jewish Hospital here.

Guinea pigs will give way to potatoes as a medium for the diagnosis of tuberculosis as a result of the new method of detecting bacilli recently perfected by the laboratory of the hospital. The new method was outlined and announced as effective in a paper read before the American Medical Association at its recent meeting in Minneapolis by Dr. H. J. Corper, Director of Research at the hospital laboratory.

The new use of potatoes as a culture medium for the detection of tuberculosis germs will obviate to a great extent the using of guinea pigs, rabbits, dogs or other live animals in this phase of research work.

Two methods of detecting the presence of tubercle bacilli have been used by scientists, Dr. Corper points out. One consisted in the use of a stain smear, which employs the microscopic examination of the sputum of a tuberculous suspect. The second was the injection of tuberculosis germs into the bodies of guinea pigs. The former method has been found to be crude and inaccurate and productive of results only when many thousands of bacilli are present in every cubic centimeter.

The guinea pig has long been used at a medium for the detection of tubercle bacilli, because of the extraordinary sensitivity of the animal to this germ. Now, however, it has been difinitely proved that the use of a slice of ordinary potato in a culture tube, when properly treated, will display a sensitivity just as great as, and sometimes greater than, the animal.

The new method, devised by Dr. Corper and Dr. Nao Uyei, research chemist, has the added advantage of practicability. The use of guinea pigs has been both inconvenient and expensive. The cost of buying, housing, feeding and caring for the guinea pigs is now eliminated.

It is pointed out by Dr. Corper that an ordinary potato will furnish enough material for a dozen culture tubes, and is equivalent to the use of twenty guinea pigs. Considering the cost of upkeep of the animals, the new potato method is about 150 times as economical as the guinea pig method.

The perfection of the new method came after three years of effort. During that time thousands of experiments were made in an effort to improve the stain method, to test the efficiency of he guinea pig method, and finally to assure the most perfect technique for the new method. The potato method, which is expected to prove revolutionary, has the further advantage of producing results in the smallest possible time, thus making the treatment more certain and effective.

The research department of the hospital has been in operation eight years and is considered one of the best in the United States.

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