MEDICAL ENTOMOLOGY HOWARD. 567 



before he read his very notable paper before the Philosophical So- 

 ciety of Washington in the early eighties. It is worthy of note that 

 although several prominent medical men were present at the meeting, 

 including the late Drs. J. S. Billings and Robert Fletcher, the paper 

 fell utterly flat as to encouraging discussion. And when published a 

 number of months later in the old Popular Science Monthly for 1883, 

 the article attracted little attention, and, so far as I know, received 

 none of the favorable comment it deserved until George H. F. Nut- 

 tall recognized its remarkable character 16 years later and reviewed 

 it at some length in his admirable summary " On the role of insects, 

 arachnids, and myriapods as carriers in the spread of bacterial and 

 parasitic diseases of man and animals," in Volume VIII of the Johns 

 Hopkins Hospital Reports (1899) . It is certain that at the time King 

 formulated his mosquito-malaria theory he had no knowledge of 

 Laveran's discovery in 1880 of the causative organism of the disease 

 or of Manson's discoveries regarding the carriage of filiariasis by 

 mosquitoes, since he would undoubtedly have added another strong 

 argument to the 12 he so admirably formulated had he possessed this 

 information. 



But here we must leave malaria temporarily in order to discuss 

 briefly in its chronological order the extraordinary and basic dis- 

 coveries of Theobald Smith with regard to the Texas fever of cattle. 



The so-called Texas or Southern cattle fever had long been known 

 as a disease transmitted to northern cattle by cattle coming from the 

 southern regions of the United States. The region from which in- 

 fected cattle came was large and well defined and included most of 

 the Southern States. Southern cattle themselves as a rule were free 

 from any signs of disease. Cattle coming from the South in the 

 winter were harmless but when they were brought North during the 

 summer, the disease came with them. Curiously enough, it did not 

 seem to be an infection which was communicated directly from south- 

 ern cattle to northern cattle, but that the southern cattle infected the 

 ground over which they passed and then when the northern cattle 

 grazed over this same ground, they caught the fever. 



It had long been the belief among certain cattle raisers in the West 

 that ticks were the cause of this fever and that they were carried and 

 scattered everywhere by southern cattle. Many, however, disbelieved 

 this theor}^. Observations confirmatory to the tick theory, however, 

 had been made ; for example, it was noticed that when southern cattle 

 had been driven for a considerable distance, after a time, they lost 

 their power to infect pastures. Moreover, it was noticed that after 

 southern cattle had passed, the disease did not appear among northern 

 cattle grazing on their trail until 30 days or thereabouts had elapsed. 



Our knowledge was in this condition, when the investigation of the 

 disease was taken up seriously by the Bureau of Animal Industry 



