Preliminary remarks on immunity in animal kingdom 43 



intoxication are two distinct properties, so that it is impossible to 

 reduce the former to an insusceptibility to toxins. We must there- 

 fore consider these two kinds of immunity separately and we will first 

 consider the resistance of the animal organism against living infective 

 micro-organisms. 



Refractory human beings and animals may be inoculated with 

 a large number of micro-organisms without being affected. Thus 

 Opitz 1 injected 10,000,000 organisms into the blood of a dog. 

 Twenty minutes later he could find no more than 9000. It is then 

 quite natural to ask, What becomes of these micro-organisms after 

 they have made their way into the interior of the refractory organism? 

 It has been suggested that the animal gets rid of the pathogenic 

 germs much as it does of all kinds of soluble poisons. Certain of 

 these poisons, such as iodine and alcohol, are in great part eliminated 

 by the kidneys ; others, such as iron, by the alimentary canal. Why, 

 it is asked, should not micro-organisms also be eliminated by the 

 same channels? Fliigge has adopted this view and has expounded 

 it in his work on ferments and micro-organisms 2 . Moreover he 

 suggested to Wyssokowitch 3 that he should carry out a large series 

 of experiments with the object of verifying this theory. But numerous 

 very careful researches have given a result quite at variance with the 

 forecast made by Fliigge. Micro-organisms of various species, injected 

 into the blood-vessels of rabbits and dogs, were, in those cases where 

 these animals are refractory, never eliminated, either by the kidneys 

 or by any other of the excretory channels which were studied. When 

 bacteria pass into the secretions, lesions of the tissues, more or less 

 grave, are invariably present. 



This result has been repeatedly confirmed and has been accepted 

 as a general experience. The elimination of micro-organisms by the 

 urine indicates not merely the absence of immunity, but implies, 



1 also, a susceptibility of the organism. In many septicaemias, such 

 as those produced by the anthrax bacillus, the streptococcus and 

 other bacteria, or in less generalised diseases, such as typhoid fever, 

 bacteria are found in the urine, often in large numbers. In these [47] 

 cases it is a question of anything but a refractory condition even of 



i the slightest degree. 



1 Ztschr.f. Hyg., Leipzig, 1898, Bd. xxix, S. 548. 



" Fermente und Mikroparasiteu " in Ziemssen u. Pettenkofer's " Handbuch der 

 Hygiene," Leipzig, 1883. 



3 "Ueber die Schicksalc der in's Blut injicirten Mikroorganismen," Ztschr. f. 

 Hyg., Leipzig, 1886, Bd. I, S. 1. 



