FuRTHiiR Ri;si-ARcnr.s in Disi:asi:s or Plants 5')3 



Diiriny tlic (.IcL.ulc Dr. Kiiiikcl and liis associates . . . made the Institute 

 outstandini; hcadtjuartcrs tor contributions to the knowlcil^c on virus and 

 yellows diseases of plants. Rockefeller Institute for Medical Research, 

 including the branch at Princeton, were, of course, interested in virus dis- 

 eases as well as other diseases of both humans and animals. They con- 

 cluded that researches on human, animal, and plant diseases could be 

 carried on profitably in close association, the advance in each contributint; 

 to and benefiting by advances in the others. This is especially true of virus 

 diseases. Conscc]uently, Rockefeller Institute employed Dr. Kunkel to head 

 a new division of plant pathology at Princeton, New Jersey, as a part of 

 their now newly named Department of Animal and Plant Pathology. 



The DcpartmeiTt recently was transferred to the main buildings 

 of the histitute in New York. 



In 1926 Dr. Smith spoke of " living carriers of disease [as a] 

 subject [which had] grown to vast proportions and . . . become one 

 of the most important considerations of preventive medicine." *^ 

 He said, 



We now know definitely that there are human carriers of disease, that is, 

 persons who appear to be well and yet are able to transmit deadly disease 

 to others. ... Of animal carriers there are many! The trypanosome of 

 rats {T. lewisi) is transmitted by a louse; the deadly African Nagana 

 disease of horses and cattle is transmitted by a fly; the surra disease of 

 domestic animals in East Indies and the Philippines is transmitted by a fly; 

 the fatal African sleeping sickness, by the bite of another fly ; trench fever, 

 by a louse; the typhus fever of jails, ships, and camps, by a louse; the 

 bubonic plague, from rats, marmots, and ground squirrels to man, often by 

 fleas ; stomach cancer of rats, by nematodes carried in the muscles of a cock- 

 roach ; trichinosis in man, by another nematode living in the muscles of rats 

 and hogs ; the sarcoma of rat livers, by the larvae of a tapeworm of the cat ; 

 Texas fever of cattle, by a tick ; the Rocky Mountain spotted fever of man, 

 by another tick ; malarial fever of man and birds by mosquitoes ; Dengue 

 fever, by a mosquito; yellow fever, by the same mosquito {Aedes egypli) ; 

 the embryos of the worm F/Iar/a, the cause of the enormous human over- 

 growth known as Elephantiasis, are also taken up and distributed by 

 several kinds of mosquitoes; rat-bite fever is caused by a rat microbe; 

 the Tularemia fever of man is caused by a microbe living in rabbits and 

 it is transmitted by the bites of a deer fly and of a tick, and directly by 

 handling dead wild rabbits; typhoid fever and cholera are transmitted by 

 house flies; purulent ophthalmia, by flies; the Egyptian fluke disease, Bil- 

 harzia, by water snails; a similar disease of the Japanese, by another snail 

 and by crabs ; a third fluke disease of dogs, cats, and man, by eating raw 

 fish ; a tumor of frogs, by a nematode living in earthworms ; anaemia with 

 dropsy in salamanders is associated with another nematode; Malta fever in 



®^ Fifty years of pathology, op. cit., 42-43. 



