268 OPSONIC INDEX IN CHRONIC INFECTIONS 



and is difficult to explain on the opsonic theory of immunity. In 

 a chronic staphylococcic lesion, such as acne, the index may be 

 low, normal, or high, and this is also the case to a most marked 

 extent in tuberculosis. Wright classified the cases of this disease 

 into two groups : (i) strictly localized tubercle, such as lupus, 

 mild glandular cases, tuberculous abscesses, etc. ; (2) cases 

 associated with constitutional disturbances. In the former he 

 found the index uniformly low (from 0-13 to o'8S), whereas in 

 the latter there was great variation, the index being below normal, 

 or as high as 2 or more. Further researches, however, have 

 not confirmed this, and the indices of patients with lupus will 

 often be found very high. As a rule, however, the patients with 

 localized tubercle, if kept at rest in bed, will be found to have 

 a constant index, whereas in those with a progressive disease it 

 will be found to vary from day to day, being often very high. 



These variations are attributed to auto-inoculation i.e., to the 

 discharge from the lesion of a few bacteria or of a small dose 

 of bacterial toxin, which makes its way into a region suitable 

 for the elaboration of a further amount of opsonin, acting just 

 as an injection of a vaccine, and causing a negative, followed by 

 a positive phase. When the patient is kept absolutely at rest in 

 bed this does not occur, or only to a comparatively slight extent, 

 and the index is more or less steady. If, however, the patient be 

 allowed to exert himself, even slightly, or if the lesions are 

 gently massaged, specific substances are set free, auto-inoculation 

 occurs, and the index exhibits its characteristic oscillations. It 

 is also dependent to some extent on the temperature, as has been 

 shown by Inman and others, tending (in phthisis) to fall with a 

 rise of temperature, and vice vevs.i. In general, a fluctuating 

 temperature accompanies a subnormal index, a rise occurring 

 when the oscillations become less. The injection of a bacterial 

 vaccine may cause a rise of temperature, especially if the amount 

 is large, but does not always, and should not, do so. 



In chronic infections a high opsonic index does not necessarily 

 imply that a patient is doing well. In general tuberculosis the 

 index is often normal or elevated, and a rise may occur just 

 before death. This is also the case in acute infections, such as 

 erysipelas, in which a sudden and great elevation may immediately 

 precede the fatal issue (Fig. 63). 



These results are difficult to harmonize with the opsonic theory, 

 but Wright points out that it is not sufficient for there to be 



