412 BACTERIOLOGY. 



the induction of increased energy on the part of the 

 wandering cells, preparing them thus for the more 

 difficult task of destroying the more virulent organisms 

 with which the animal is subsequently to be inoculated. 



The experiments of G. and F. Klemperer ^ upon acute 

 fibrinous pneumonia, though too limited in extent to 

 be accepted as conclusive, have, nevertheless, offered a 

 number of most significant suggestions, not only in 

 connection with several obscure features of this disease, 

 but also in relation to the establishment of tissue 

 resistance. 



They found but little difficulty in affording immunity 

 to animals that are otherwise susceptible to the patho- 

 genic action, of the organisms concerned in the pro- 

 duction of this disease,^ by the introduction into their 

 tissues of the products of growth of the organisms from 

 which the latter had been separated. The immunity, 

 thus produced is seen in some cases to last as long as 

 six months ; again it is seen to disappear suddenly in a 

 way not to be explained. It was seen in one case to be 

 hereditary. 



The energy of the substance that has the power of 

 affording immunity was seen to be very much increased 

 by subjecting it to temperatures somewhat higher than 

 that at which it was produced by the bacteria. The 

 Klemperers found that if this substance was heated 

 to a temperature of from 41° to 42° C. for three or 

 four days, or to 60° C. for from one to two hours, 

 intravenous injection was followed by complete im- 

 munity in from three to four days ; whereas, if the 



1 G. and F. Klemperer : Berliner klin. Woohensehr., 1891, Nos. 34 and 35. 



2 Animals do not, as a rule, present the pneumonic changes seen in human 

 beings. The introduction of the micrococcus lanceolatus into their tissues 

 results, in the case of susceptible animals, in the production of septlcsemia. 



