xvi INTRODUCTION 



of there being an increase the number is below the normal it is a 

 bad sign. During the course of this disease the reappearance of 

 the eosinophils is a favorable sign, indicating that the crisis is 

 passed. In an anemia in which the hemoglobin is much lessened 

 while the number of red corpuscles remains nearly normal, the 

 indications for a prompt improvement under the administration 

 of iron are good; while but little improvement is to be expected 

 when the amount of hemoglobin in each corpuscle is normal and 

 practically no improvement when the hemoglobin index is above 

 normal, iron being practically contraindicated in the more severe 

 cases when the blood shows very large red corpuscles each having 

 an increased amount of hemoglobin. In examinations for sound- 

 ness the blood offers valuable aid, as has been pointed out by 

 Moore. When an examination reveals that the blood is not nor- 

 mal a close search for the cause is indicated. The presence of 

 disease, unsuspected it may be by the ordinary means of examina- 

 tion, may be shown by the blood. Though the fact that an animal's 

 blood is normal is not indicative that the animal is sound, it is 

 an added safeguard, and on the other hand an animal having an 

 abnormal condition of the blood cannot be certified as being 

 sound. 



In interpreting the results of an examination of the blood it 

 must be kept in mind that this is but one symptom. A diagnosis 

 should be made after duly considering all of the symptoms avail- 

 able. The blood is not supposed to supplant other means of ex- 

 amination, but is to be used with them. In fact it will have a 

 strong tendency to sharpen one's powers of observation for other 

 symptoms. 



