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SCIENCE 



[N. S. Vol. XLIV. No. 1132 



perimentally from animal to animal by 

 flies but it has not yet been shown that flies 

 play a significant role in human trans- 

 mission. As to the fly it is difficult to de- 

 termine how important it is in the trans- 

 mission of a number of infections. 



While much suggestive evidence exists 

 concerning the role of animals in carrying 

 certain diseases whose origin is still ob- 

 scure, on the other hand, there is in the 

 literature much loose speculation as to the 

 role animals play in many such diseases. 

 Superstition and tradition enter at times 

 to aid this speculation. The older litera- 

 ture contains many articles on the role of 

 dogs, cats, and other domestic animals in 

 the transmission of the various contagious 

 diseases, especially diseases of children. 

 Syphilis, measles, scarlet fever, smallpox, 

 etc., have been thought to be transmitted 

 by lice, bed bugs, flies and other blood- 

 sucking insects. Occasional instances of 

 such modes of transmission have perhaps 

 occurred or are possibilities, but there have 

 been much worthless discussion and specu- 

 lation on these subjects. 



In the solution of the various problems 

 that arise in connection with prevention of 

 human-animal diseases no one rule can be 

 established for their control. In the first 

 place each disease must be studied by itself 

 and its natural history in detail should be 

 known in order to intelligently cope with 

 it. Upon personal hygiene and care in all 

 matters concerning diet, clothes, housing 

 conditions and our relations to animal life 

 as well as upon close observance of sanitary 

 rules will largely depend the solution of 

 these problems. 



As already stated nearly all of these dis- 

 eases are easily preventable once the true 

 natural history of the disease is known. 

 The serious problem then is usually the 

 education of the public. To illustrate, in 

 hydrophobia prevention centers around the 

 problem of the muzzling of dogs. This has 



been known for decades, yet the American 

 people prefer to have 5,000 persons, 

 mostly children, bitten each year and 

 a hundred or more deaths, than to subject 

 their dogs to the discomfort of a muzzle 

 and to destroy the stray and worthless curs 

 of the street. It should be said that this 

 has been true in the past. Now the prob- 

 lem has become far more serious. In our 

 western states rabies has spread during the 

 past year to the coyotes, wolves and other 

 wild animals which wander about biting 

 domestic animals, especially stock, and 

 even attacking persons, particularly school 

 children. Our government has now spent 

 large sums in an attempt to control the dis- 

 ease, but, once in wild animals, it is known 

 to be very difficult to eradicate. Thus the 

 matters stand at present with this human- 

 animal disease. Such an experience should 

 serve as an example, and many others 

 might be given, in this matter of the im- 

 portance of animals to human diseases and 

 their control. 



The study of comparative pathology, it 

 would seem, should occupy a more promi- 

 nent place in the curricula of our universi- 

 ties and medical schools than it has in the 

 past. "When we consider the fundamental 

 character of the studies in this field of 

 pathology — the work of Jenner, of Pas- 

 teur, of Koch, of Theobald Smith and espe- 

 cially of a great group of investigators in 

 recent years on cancer and on tropical dis- 

 eases in man and animals— the truth seems 

 evident that in the study of disease and in 

 its presentation to students such an impor- 

 tant field should not be slighted. Our study 

 of disease in medical and veterinary insti- 

 tutions should be at least as broad and as 

 comparative as is the study of zoology or 

 botany. In order to understand the nat- 

 ural history of many diseases comparative 

 studies are absolutely necessary. It would 

 undoubtedly be advantageous both from 

 a humane as well as from a scientific 



