432 DISEASES OF CATTLE. 



ing death. The pulse and respiration are usually much more rapid 

 than during health. 



Other symptoms in addition to those mentioned have been described 

 by observers, but they do not seem to be constant, and only the above 

 are nearly always present. As the end approaches emaciation becomes 

 very marked, the blood is very thin and watery, and the closing of any 

 wound of the skin by clots is retarded. The animal manifests increas- 

 ing stupor and may lie down much of the time. Signs of delirium have 

 been observed in some cases. Death occurs most frequently in the 

 night. 



The course of the disease is very variable in duration. Death may 

 ensue in from three days to several weeks after the beginning of the 

 fever. Those that recover ultimately do so very slowly, owing to the 

 great poverty of the blood in red corpuscles. The flesh is regained but 

 very gradually, and the animal may be subjected to a second though 

 mild attack later on in the autumn, which pushes the full recovery on- 

 ward to the beginning of winter. 



In the mild type of the disease, which occurs in October and Novem- 

 ber, symptoms of disease are well nigh absent. There is little if any 

 fever, and if it were not for loss of flesh and more or less dullness the 

 disease might pass unnoticed, as it undoubtedly does in a majority of 

 cases. If, however, the blood corpuscles be counted from time to time 

 a gradually diminishing number will be found, and after several weeks 

 only about one-fifth or one-sixth of the normal number are present. It 

 is, indeed, surprising how little impression upon the animal this very 

 impoverished condition of the blood appears to make. It is probable, 

 however, that if two animals kept under the same conditions, one healthy 

 and the other at the end of one of these mild attacks, be weighed, the 

 difference would be plainly shown. 



Pathological changes observable after death. In the preceding pages 

 some of these have already been referred to in describing the nature 

 of the disease. It is very important at times to determine whether a 

 certain disease is Texas fever or some other disease, like anthrax, for 

 example. This fact can, as a rule, be determined at once by a thorough 

 microscopic examination of the blood. The necessary apparatus and 

 the requisite qualifications for this task leave this method entirely in 

 the hands of experts. There is, however, a considerable number of 

 changes caused by this disease, which may be detected by the naked 

 eye when the body has been opened. These, put together, make a mis- 

 take quite impossible. The presence of small ticks on the skin of the 

 escutcheon, the thighs, and the udder is a very important sign in herds 

 north of the Texas fever -line, as it indicates that they have been brought 

 in some manner from the South and carried the disease with them, as 

 will be explained later. Another very important sign is the thin, watery 

 condition of the blood, either just before death or when the fever has 

 been present for four or five days. A little incision into the skin will 



