DISEASES OF CATTLE 323 



ness 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 ap- 

 pears to make. It is probable, however, that if two animals kept un- 

 der 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 preced- 

 ing 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 nec- 

 essary 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 mistake 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 indi- 

 cates that they have been brought in some manner from the South 

 and carried the disease with them, as will be explained later. An- 

 other 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 enable anyone to de- 

 termine this point. Frequently the skin is so poor in blood that it 

 may require several incisions to draw a drop or more. 



The changes in the internal organs, as found on postmortem 

 examinations are briefly as follows: The spleen, or milt, is much 

 larger than in healthy animals. It may weigh three or four times 

 as much. When it is incised the contents or pulp is blackish, and 

 may even swell out as a disintegrated mass. The markings of the 

 healthy spleen are all effaced by the enormous number of blood cor- 

 puscles which have collected in the spleen and to which the enlarge- 

 ment is due. Next to the spleen the liver will arouse our attention. 

 It is larger than in the healthy state, has lost its natural brownish 

 color, and now has on the surface a paler yellowish hue. When it 

 is incised this yellowish tinge or mahogany color, as it has been called 

 by some, is still more prominent. This is due to the large amount 

 of bile in the finest bile capillaries, and as these are not uniformly 

 filled with it the cut surface has a more or less mottled appearance. 

 This bile injection causes in many cases a fatty degeneration of the 

 liver cells, which makes the organ appear still lighter in color. ^ 



In all cases the gall bladder should be examined. This is dis- 

 tended with bile, which holds in suspension a large quantity of yel- 

 low flakes, so that when it is poured into a tall bottle to settle fully 

 one-half or more of the column of fluid will be occupied by a layer of 



