236 SCIENCE PROGRESS. 



body is the toxine of tetanus destroyed by the anti- 

 toxine of the blood or serum. These bodies re-act only by 

 the mediation of the organisation of the body. The term 

 antitoxine is a misnomer, since it is a substance which only 

 under certain circumstances confers immunity, and this it 

 can only effect when actively operative within the or- 

 ganism (8). It is not necessary here to discuss either this 

 view or the one that is opposed to it, which, while not 

 denying that there may be methods of protection other 

 than phagocytosis, affirms that the part played by phago- 

 cytic action is of all these the most widely spread and the 

 most efficacious. The part played by eosinophile cells in 

 the acute leucocytosis, which occurs at the seat of inocula- 

 tion of micro-organisms, has been pointed out by researches 

 in this country. When we consider the conflicting views as 

 to the origin of the immune condition, the various grades 

 of this, the distinction between the really immune condition 

 where a pathogenic organism cannot multiply within the 

 body, and the toxine-resistant state where the animal 

 experimented upon is not invaded by micro-organisms and 

 is at the same time refractary to the toxines these pro- 

 duce (9) ; the distinction between passive and active im- 

 munity, drawn by Ehrlich ; the temporary duration of 

 artificial immunity, and the impossibility of employing any 

 test other than a physiological one for determining the 

 variability of the refractary state, it becomes abundantly 

 evident from the complexity of the subject that no absolute 

 statement as to the origin of immunity is possible, and, 

 further, statements relative to the behaviour of any specific 

 pathogenic microbe within the body can only be employed 

 with limitations when considering the mode of action of 

 any other micro-organism. 



A measure of experimental immunity or degree of toxine- 

 resistance can be mathematically obtained by Ehrlich's 

 method (10), where any grade of resistance is expressed by 

 a number which gives the multiple of the lethal dose for 

 normal individuals of equal weight, which the tested animal 

 can withstand without death. The method of Behring and 

 Wernicke (11) also indicates the degree of immunity by a 



