SPLENIC OR PERIODIC FEVER OF CATTLE. 97 



fifty head of Texas cattlo. Some forty clays after they left, about the 18th of August, 

 the disease broke out among uiy milch cows and heifers, and work cattle. 



Thus we see that from thirty to forty days usually elapse from the 

 placing- of Texau stock ou a pasture and the niauifestation of disease to 

 the stock owners of the neighborhood. 



The first indication which attracts special attention is usually the 

 death of a cow or steer. It is evident that this very imperfectly 

 defines the length of the incubative stage, inasmuch as in all probability 

 the native stock is not instantly poisoned, and then the disease is active 

 some days before symptoms, such as an ordinary farmer may detect, or 

 deaths occur. It is probable, however, that from eighteen to twenty-five 

 days are usually required for the poison to exert any marked influence 

 on an animal's health, and then the second stage occurs. 



II. The period of invasion. — My examination of animals in apparent 

 health, picked out of a diseased herd, indicates that the invasion of the 

 malady is characterized by an elevation of temperature. Here we have 

 some similarity with rinderpest ; but since there is not the same uni- 

 formity in the length of the incubative stage in splenic fever that there 

 is in the Russian murrain, it is probably more common to find steers 

 with a normal temperature in a herd infected with the first, than the 

 last disease. 



The first opportunity I had of testing this matter was on the 31st of 

 July, at Tolouo, where we saw the first animal of a herd, a yearling, 

 lying dead. I began bj^ examining a well-bred short-horn cow in bloom- 

 ing condition, and found her temperature to be 10G° Fahr. ; second was 

 106.50 Fahr. ; third 106.7° Fahr. ; fourth 106.7° Fahr. ; fifth 106.1° Fahr. ; 

 sixth 107.2° Fahr. ; seventh 106.7° Fahr. ; eighth 107.2° Fahr. ; ninth 

 104.2° Fahr.; tenth 106.7° Fahr. 



At Junction City I examined the healthiest-looking animals of an 

 infected herd, and noted the following temi^eratures with one of Casel- 

 la's self-registering thermometers: 



First 104.6° Fahr.; second 106.0° Fahr.; third 102.8° P'ahr. ; fourth 

 107.7° Fahr.; fifth 103° Fahr.; sixth 102.4° Fahr.; seventh 105.8° 

 Fahr.; eighth 103.4° Fahr.; ninth 107.2° Fahr.; tenth 102.2° Fahr.; 

 eleventh 107.8° Fahr.; twelfth 102.6° Fahr.; thirteenth 103° Fahr,; 

 fourteenth 102.4° Fahr.; fifteenth 102.6° Fahr.; sixteenth 102.8° Fahr.; 

 seventeenth 102.6° Fahr, 



I examined three sick steers in this herd, and found their temperature 

 to be respectively 104° Fahr., 107.2° Fahr., and 105.8° Fahr. Of the 

 api)arenfly healthy ones no less than six indicated a temperature as 

 high or higher than the naturally deceased aninuds, and in all the tem- 

 perature was really exaltetl. 



On Smoky U ill we inspected cattle in blooming health, so far as exter- 

 nal a])i)earaiiccs would indicate. We had found a case of si)lenic fever 

 there, and determined to have some steers caught with the lasso and 

 examined, with the following result : 



7 



