THE SPLENIC FEVER. 129 



to death. There is doubtless something tangible and ponderable, which some future 

 chemist may reveal, that renders the grasses, and perhaps the waters, of the South so 

 deleterious. 



The disease, therefore, to which the third of the annexed reports refers, is an indigen 

 ous or enzootic malady, susceptible of moderate extension by the manner in which the 

 grasses of healthy regions are modified by the manure scattered broadcast from the systems 

 of southern herds. It is not a contagious plague, and will probably cease when the agri 

 culture of the South is fairly and fully developed. 



Not so with the destructive malady, the lung plague or epizootic pleuropneumonia, 

 which is silently but seriously ravaging the Eastern States. This affection constitutes the 

 subject of my second report. Its method of propagation, by diffusion of a specific animal 

 poison or virus through the air, offers an instructive contrast to the comparatively harm 

 less disease of the South. The lung plague kills slowly and surely wherever it penetrates, 

 without regard to latitude, breeds, soils, conditions of weather, or systems of cultivation. 

 It can be stamped out; and its propagation in a mild form may be resorted to for the pro 

 tection of cattle that have been suspected of entering an infected area. It attacks animals 

 but once in their lifetime, and presents all the characters of specific eruptive fevers, of which 

 the human or ovine small-pox may be regarded typical. 



A few words may not be considered inappropriate as to the nature of our investiga 

 tions. They have extended over a period of ten months, and in all parts of the United 

 States except in the far west. The furthest point west which was reached is near the 

 terminus of the Kansas Pacific Railroad, and southwest to Corpus Christi. The great object 

 in view has been to determine and demonstrate with precision the causes and signs of the 

 several diseases examined, with a view to the suggestion of means of prevention and cure. 

 The history of special outbreaks, the methods of extension, the essential symptoms and 

 pathological changes indicated by sick animals, and the institution of careful personal in 

 quiries among those who have witnessed the maladies at different periods, have engaged 

 special attention. 



We were first in having opportunities for a careful study of the changes in tempera 

 ture which occur in splenic fever, and, taken in conjunction with similar observations orig 

 inally made by us in relation to the rinderpest or Russian murrain, and since in numerous 

 outbreaks of pleuropneumonia, it will be found that very definite and highly practical 

 results may be anticipated from persistence in this method of observation. Indeed, so 

 important is the matter in connection with the entire subject of comparative pathology, 

 that it may not be deemed inappropriate to give a resume of our operations on this par 

 ticular point. 



Last July we first used the only available thermometers that could be obtained in 

 Chicago, centigrade thermometers, of French manufacture. The Surgeon General, how-, 

 ever, kindly acceded to a request made through the Department of Agriculture, and two 

 carefully-compared self-registering thermometers, made by Mr. L. Casella, of London, were 

 forwarded to the west for the purpose of our inquiries. With these we were enabled to 

 correct and verify the earlier observations. The normal temperature of cattle varies from 

 100 to 102 Fahrenheit. The average temperature of Texan cattle is from one to two 

 degrees higher than that of northern steers. There may be accidental deviations, of which 

 the most noticeable is at the period of oestrum, when a cow may indicate a temperature as 

 17 



