200 Dr. A. E. Wright and Staff-Surgeon S. T. Keid. [Oct. 21, 



The inference drawn from these data that the patient was suffering from 

 some active form of tuberculosis was confirmed (a) by the discovery by an 

 independent observer of a lesion in the apex of one lung ; (b) by the subsequent 

 development of an abscess of an obviously tubercular character ; and (c) by 

 the marked improvement in health which has followed upon inoculation with 

 tubercle vaccine. 



(2) Conclusions which may be arrived at where we have at disposal the 

 result of an isolated blood examination. 



(a) Where an isolated blood examination reveals that the tubercido-opsonic power 

 of the blood is low, we may — according as we have evidence of a localised bacterial 

 infection or of constitutional disturbance — infer with 'probability that we are 

 dealing with tuberculosis — in the former case with a localised tubercular infection, 

 in the latter with an active systemic infection. 



(b) Wliere an isolated blood examination reveals that the tuberculo-opsonic 

 power of the blood is high, we may infer that we have to deal with a systemic 

 tuberculous infection which is active, or has recently been active. 



(c) Where the tuberculo-opsonic power is found normal, or nearly normal, 

 while there are symptoms which suggest tuberculosis, we are not vjarranted, 

 apart from the further test described below, in arriving at a positive or a 

 negative diagnosis. 



Discrimination of Tubercular Blood from Normal Blood by the aid of the 

 Phagocytic Test Conducted with Serum which has been subjected to a 

 Temperature of 60° C. 



The further criterion to which reference was made in the preceding 

 paragraph is the following : — 



When a serum is found to retain in any considerable measure, after it has 

 been heated to 60° for 10 minutes, its power of inciting phagocytosis we may 

 conclude that " incitor elements "* have been elaborated in the organism either in 

 response to auto-inoculations occurring spontaneously in the course of tubercular 

 infection, or, as the case may be, under the artificial stimulus supplied by the 

 inoculation of tubercle vaccine. 



A typical selection from the very extensive body of observations which 

 furnishes the basis of the above statement is presented in Tables II 

 and III. 



It will be seen from these tables that in practically every case where a 

 reaction to tubercular infection may be assumed to have taken place, 



* The term " incitor elements " (Latin, incito, I urge forward, I hasten, I bring into 

 rapid movement) is here employed in lieu of a more specific term, in order not to prejudge 

 the mode of action of the element in the heated serum which promotes phagocytosis. The 

 nature of the incitor element is considered in the next following communication. 



