284 CLINICAL BACTERIOLOGY AND H^MATOLOGY 



This is said to occur before the hooping occurs and to be of 

 diagnostic value, but leucocytosis with lymphocytosis is so 

 common in children that little value should be attached to it 

 unless really high figures are found. 



INFLUENZA. Here the blood-count may be of value, since 

 in contradistinction to the majority of acute febrile diseases 

 there is no leucocytosis if complications are absent. In other 

 febrile diseases of rapid onset pneumonia, tonsilitis, rheu- 

 matic fever, septic affections, plague, etc. leucocytosis is 

 almost constant. 



RHEUMATISM. Except in the very mildest cases there is 

 leucocytosis, and, according to Turk, Ewing, and others, when 

 there are more than 20,000 there is almost certainly some com- 

 plication, such as endocarditis, pericarditis, pneumonia, or 

 hyperpyrexia. I believe this may be taken as a safe general 

 rule, though exceptions do occur. 



Turk believes that a clue to prognosis may be got from the 

 percentages of eosinophiles present; with a proportion above 

 the normal the case is likely to be a mild one. 



TUBERCULOSIS. There is usually marked anaemia of the 

 secondary type, but in cases with sweating and diarrhoea this 

 may be masked by the concentration of the blood; an ap- 

 parent improvement in this respect may in reality be a bad 

 sign. The leucocytes are usually normal, though the lympho- 

 cytes may be rather high. 



Where secondary septic infection takes place e.g., in a 

 vomica the blood is that of sepsis ; there is a variable leucocy- 

 tosis, excess of polynuclears, and advancing anaemia. 



The blood-count is not of much value in the diagnosis of 

 tubercle; it is of some value in prognosis. Increase in the 

 polynuclears and in the grade of anaemia are bad signs in 

 phthisis. 



There are one or two precautions to be noted in special 

 cases. In tuberculous empyema there is frequently a 

 secondary infection, and the presence of a leucocytosis does 

 not show that the disease is not tuberculous; the same thing 

 applies to tuberculous abscesses in other parts, including the 

 joints. 



Tuberculous meningitis appears to offer the most marked 

 exception to the rule, that uncomplicated tubercle does not 

 cause leucocytosis. Here there is often moderate leucocytosis, 



