808 REPORT— 1894. 



cause of subsequent immuDity,the well-known fact that in erysipelas the parts first 

 attacked may be recovering while the disease is spreading elsewhere would lead 

 us to suspect that these parts have learnt to resist the streptococcus while the rest 

 of the body is still susceptible. 



To inquire whether erysipelas confers any such local immunity was the object 

 of the following experiments : — 



Fourteen rabbits which had recently suSered from erysipelas in the right ears 

 were again inoculated with the streptococcus, this time in both ears. In each case 

 a control animal, inoculated at the same time, suHered from typical erysipelas. 

 The results were as follows: Left ears. — In four, only a little redness about the 

 seat of inoculation. In four, erysipelas commenced, but aborted on the third or 

 fourth day. In six, typical erysipelas. Right ears. — Inflammation rapidly appeared, 

 affected the whole part, and subsided in twenty-four to ibrtj'-eigbt hours. Culture 

 experiments, which invariably revealed the presence of streptococci in the early 

 stages of true erysipelas, showed that micro-organisms were absent from the 

 inflamed right ears. Thus all the right ears showed themselves to be immune, 

 •while nearly one half the left ears proved as susceptible as those of the control 

 animals. Hence we conclude that the first attack of erysipelas had conferred a 

 very complete local immunity. That erysipelas confers some degree of general 

 immunity is already well known from the work of Fehleisen, Roger, and others. 



Further experiments showed that this local immunity lasted only so long as 

 any thickening remained in the ears after erysipelas. Its duration depended, there- 

 fore, on the severity of the first attack. 



The inflammation which resulted from inoculations of ears previously aftected 

 we thought to be a reaction against the poisons actually introduced, and not due to 

 the vital activity of the cocci, because we could obtain no evidence that these had 

 multiplied and invaded the ear. This opinion was put to the test by injecting into 

 both ears of animals, which had recently suffered from erysipelas in one ear, small 

 quantities of concentrated filtered cultures, and in one case the streptococci them- 

 selves destroyed by heat. In these experiments a somewhat violent inflammation, 

 of short duration (two to three days), resulted in the right ears, and a less severe 

 but more prolonged infiammation in the left. An important difference was in the 

 time of onset of this infiammation, which in the previously afi'ected ears appeared 

 many hours earlier than in the others ; a diflisrence similar to that which had 

 already been observed to result from the inoculation of living cocci under the same 

 conditions. Thus it appears that parts which have recently suffered from erysipelas 

 become more quickly and intensely inflamed when subjected to the action of the 

 products of the streptococcus than do other parts of the same animal. And when 

 we remember that this tendency to inflammation goes hand in hand with a notably 

 greater resistance to the living microbe, we are led to regard it as beneficial in its 

 action, aud an important factor of local immunity ; an opinion in harmony with 

 that already expressed by Metchnikofl' and others — viz. that infiammation is a 

 protective process. 



4. A Form of Experimentally-produced Immunity. 

 By J. LoRRAiN Smith, M.A., M.D., and E. Trevithick, M.B. 



_ The occurrence of fibroid changes in the lungs when these are due to the 

 irritant effect of inhale! dust is, according to clinical authorities, associated with 

 increased liability of the lungs to infection by the tubercle bacillus. On the other 

 hand, there is much clinical as well as experimental evidence to show that the 

 condition of inflammation in the tissues is in general accompanied by an increased 

 power of resisting the invasion of microbes. 



The following experiments are brought forward to show that, in its early 

 staees. the inflammation due to irritating dust in the pleural cavity increases the 

 difficulty of infecting the animal in this locality with the bacillus pyocyaneus. 

 The experiments were made on guinea-pigs and rabbits. 



The dust (pounded glass) was placed in a bottle containing a quantity of 

 water. This was sterilised, and before injection the dust was stirred up and mixed 



