VACCINE THERAPY IN THEORY AND PRACTICE 613. 



was the correct one. If the boil is worse, the dose was pro- 

 bably incorrect ; and even when this has happened no really 

 serious damage is done, and the physician may fairly accept 

 the risk. But in other infections, such as tubercular disease 

 of joints, in which weeks may elapse before any marked clinical 

 change is produced, either for better or worse, it is essential 

 for the physician to have some other guide as to whether he 

 is doing right or wrong. Some observers, notably Latham,, 

 claim that in phthisis the temperature is an accurate guide, 

 and Latham has published a series of double charts with curves 

 of the opsonic index and of the temperature, and these curves 

 vary inversely in a very remarkable manner. 1 He argues from 

 these that a high temperature means a low index, and that 

 dosage and spacing of inoculations may be regulated thereby. 

 This leaves out of account the possibility of high temperatures 

 being due to infections by other organisms — a possibility not- 

 to be neglected. Moreover, other observers have published 

 similar charts in which the two curves run almost precisely 

 parallel, and others again in which no correlation can be 

 traced. 2 Observations are not yet sufficiently numerous, nor 

 in sufficient agreement, to allow of the temperature being con- 

 sidered a reliable guide. Broadly speaking, it is clear that if 

 the principles of vaccine therapy are sound, clinical improve- 

 ment must be accompanied by a rising opsonic index ; but to 

 say that at any given moment the height of the index can be 

 inferred from the clinical condition is to deny that this condi- 

 tion can be influenced by anything but an immunising response. 

 It appears, then, that it is necessary to estimate the anti- 

 bacterial power of the blood. Now the blood is known to 

 contain a considerable number of different anti-bacterial sub- 

 stances, and the question arises whether all of these are to 

 be estimated, or whether the condition of one may be regarded 

 as a measure of the whole. The blood has been shown to 

 contain different bodies which agglutinate, kill, dissolve, and 

 "opsonise" bacteria. The attempt to estimate the whole of 

 these would clearly occupy a great deal of time ; secondly, we 

 have at present no means of demonstrating the action of certain 

 of these bodies against certain bacteria — for instance, the 

 bactericidal power of serum can be demonstrated against 



1 Latham, Proc. Roy. Soc. Med., April 1908. 



2 Wright and others, Lancet, Nov. 2, 1907. 



