164 DEPARTMENT OF AGRICULTURE. 



Not SO witli the destructive malady the hiug pUigue, or epizoiitic 

 ph'iiro-pneumoiiia, which is silently but seriously ravaging the P^asteru 

 States. This affectiou coustitutes the subject of my sec5ud report. Its 

 method of propagation, by diffusion through the air of a specilic animal 

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

 less disease of the south. The lung ])laguc hills slowly and surely wher- 

 ever it penetrates, without regard to latitude, breeds, soils, conditions of 

 weather, or systems of cultivation. It can be stamped out ; and its propa- 

 gation in a mild form may be resorted to for the protection of cattle that 

 have been suspected of eutering an infected area. It attacks animals 

 but once iu their lifetime, and presents all the characters of specilic erup- 

 tive fevers, of which the human or oviue small-pox may be regarded 

 typical. 



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

 our investigations. They have extended over a period of ten months, 

 and iu all parts of the United States except in the far west. The turthest 

 point w est we have reached has been near the terminus of the Kan- 

 sas Pacific railroad, and southwest to Corpus Christi. The great object 

 iu view has been to determine and demonstrate with precision the causes 

 and signs of the several diseases examined, with a view to the sugges- 

 tion of means of prevention and cure. The history of special outbreaks, 

 the methods of extension, the essential symptoms and pathohigical 

 changes indicated by sick animals, and the institution of careful per- 

 sonal inquiries among those who have witnessed the maladies at differ- 

 ent periods, have specially engaged our attention. 



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

 in temperatiu-e which occur in splenic fever, and, taken in conjunction 

 \\ith similar observations originally made by us in relation to the rind- 

 erpest or Kussian murrain, and since in numerous outbreaks of pleuro- 

 pneumonia, it will be found that very definite and highly practical re- 

 sults 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 particular point. 



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

 obtifined in Chicago, Centigrade thermometers, of French nuinufacture. 

 The Surgeon General, however, kindly acceded to a request made through 

 the Uei)artment of Agriculture, and two carefully compared self-regis- 

 tering thermometers, nmde by Mr. L. Casella, of London, were forwarded 

 to the west for the purpose of our incpiiries. With these we were ena- 

 bled to correct and verify the earlier observations. The normal tempera- 

 ture of cattle varies from 100° to lO^o Fahrenheit. The average tem- 

 perature of Texan cattle is from one to two degrees higher than that of 

 lunthern steers. There may be accidental deviations, of which the most 

 noticealde is at the period of a-strum, wlien a cow nuiy indicate a tem- 

 perature as high as 100° Fahrenheit. It is, however, reularkable how 



