THE USE OF DRUGS IN THE TREATMENT OF DISEASES
                        CAUSED BY WORMS.

                                          BY

                  MAURICE C. HALL, PH.D., D.Sc., D.V.M.,

Chief, Zoological Division, Bureau of Animal Industry, U. S. Department of Agriculture,
                                    Washington, D. C.

(Reprinted from the Journal of Comparative Pathology and Therapeutics, Vol. XLIII, part 2, June 1930.)

      Since 1915 the writer's principal scientific interest has been in the field of
anthelmintic medication. In the fifteen years from 1915 to 1930 the investigation of
anthelmintics has progressed to the point where it may now be admitted to be
actually scientific in approach, method, and technic and the number of investigators
in this field has increased in proportion to an immense increase in interest in the
subject. From 1881, the year in which several important treatments for human
anchylostomiasis were proposed, following the recognition of the fact that hook-
worms were serious pathogens responsible for Egyptian chlorosis, tropical anæmia,
and the St. Gothard Tunnel disease, to 1915, there had been an increasing interest
in the development of anthelmintic medication, but for the most part the studies
of this period were along the lines of critical empiricism and increasingly close
clinical observation. Previous to 1881 anthelmintic medication was mostly a
matter of uncritical empiricism.

      In 1915 it was practically impossible to give an intelligent answer to a question
in regard to anthelmintic medication in the field of veterinary medicine. Books
and journals contained endless formulæ incorporating scores of drugs for the re-
moval of worms from domesticated animals, but there was no critical evidence on
which to judge the value of these drugs. The most that was offered was clinical
experience, and as clinicians are a mixed lot, comprising good observers and sound
thinkers on one hand, and poor observers and un-sound thinkers on the other, the
recommendations of innumerable John Does and Richard Roes, unknown to the
reader, could not be sorted to distinguish the good from the bad.

      This situation was extremely uncomfortable for the Zoological Division of the
Bureau of Animal Industry, United States Department of Agriculture. A con-
stant stream of questions in correspondence called for answers in keeping with the
standing and reputation of the Bureau of Animal Industry. It was only possible

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