CHAPTER VII 

 GENERAL AND INFECTIOUS DISEASES 



General considerations. In the various diseases the changes 

 in the blood, when changes are found, depend on the character 

 of the pathological processes present and also on the nature of 

 the exciting cause. In acute exudative inflammations we find 

 as a rule an increase in the number of leucocytes, a large per- 

 centage of which are poljinorphonuclears. The inflammation 

 may be in the lungs, in the testes, in muscle, glands, peritoneum, 

 pleura, in other organs; the disease may be a wound infection, 

 pleuro-pneumonia, strangles, tetanus and the like; polynuclear 

 leucocytosis has been found in all of these. The effect on the 

 blood has been found to vary with the nature of the exciting 

 cause. The character of the lesion produced may vary with 

 the cause. For example, the same cause may in one instance 

 produce an exudative inflammation as pneumonia, in another 

 instance a septicemia may result. Again different effects may 

 be observed in the course of the same disease in different stages, 

 e. g., when an acute inflammation becomes a chrome productive 

 inflammation, as is sometimes observed in strangles. 



In certain of the infectious diseases substances may be found 

 in the blood that are characteristic of the particular disease, the 

 character of the pathological process or the particular organ 

 mainly affected not having a noticeable effect on these substances. 

 In glanders, streptococcic infections, typhoid fever, malta fever 

 and bacillary dysentery, specific agglutinins or precipitins or both 

 have been found in the blood of affected individuals. Some of 

 these substances are valuable aids for the diagnosis of the particu- 

 lar affection of each. 



Changes produced in the blood in acute febrile disorders. 

 Certain changes have been observed in the blood common to 

 the acute febrile disorders. In fevers the number of red cor- 

 puscles is reduced, though the anemia may not be apparent for 

 a time. During the earlier stages there is a contraction of the 



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