JOINAL OF AGRIdMAL RESEARCH 



Vol. XII 



Washington, D. C, February i8, 1918 



No. 7 



EFFICACY OF SOME ANTHEIyMINTICS 



By Maurice C. Kali, ^ formerly Assistant Zoologist, and Winthrop D. Foster, Junior 

 Zoologist, Zoological Division, Bureau of Animal Industry, United States Department 

 of Agriculture 



INTRODUCTION 



Although the use of anthelmintic treatment is an old practice in human 

 and veterinary medicine, the efficacy of the various substances employed 

 as anthelmintics is not well known. What information is available is 

 based largely on clinical observations, efficacy being judged to a large 

 extent on a consideration of the improvement or lack of improvement in 

 the patient's health after treatment. In other instances the efficacy of 

 the treatment has been checked by fecal examinations for worms passed 

 and for eggs persisting in the feces; but, while this method gives real and 

 valuable information, it is somewhat inexact. The methods employed 

 for examining feces for worms passed are often rather casual; and nega- 

 tive findings in examining feces for eggs, especially when a small number 

 of preparations are examined for only a few days after treatment, are 

 not always conclusive. 



A more satisfactory method of investigating anthelmintic efficacy is to 

 administer treatment to animals, to collect all feces passed for a number 

 of days, to recover from them all worms present, and then to kill the 

 animals and collect all worms remaining. In this way it is possible to 

 arrive at a fair idea of the anthelmintic effect to be expected from a drug, 

 the correctness of the conclusions depending, of course, on the number of 

 experimental animals used and their degree of infestation. 



While it is thus possible to express the efficacy of a drug in the form of 

 a mathematical ratio, the writers are fully aware that such ratios, except 

 when based on extensive data, can not be considered an accurate index 

 of the efficacy of the drug, since many factors, not entirely within con- 

 trol, such as the individual reaction of the animal, the amount of material 

 in the alimentary tract, and the potency of the drug, all enter into the 

 problem. 



In carrying out this series of experiments the plan of the writers was 

 to test as many drugs as possible having a known or alleged anthelmintic 

 value, abandoning those which gave no results, and making further 



Journal of Agricultural Research, 



Washington, D. C. 



Iz 



' Resigned September 19, 1916. 



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Vol. xn. No. 7 

 Feb. 18, 1918 

 Key No. A— 34 



