92 ANTIGENS AND ANTIBODIES 



result is brought about with dead cultures. On the other hand it 

 can be shown that the process of agglutination does not lead to the 

 destruction of the bacteria; these may, in fact, multiply in the agglu- 

 tinated state. Under certain conditions they will then grow out in 

 threads which are twisted upon themselves so as to form complicated 

 skeins a behavior w T hich was first noted by Pfaundler and which is 

 spoken of as Pfaundler's Fadenreaktion, i. e., thread reaction. 



Gruber, Durham, Baumgarten a. o., at first looked upon the 

 agglutinins as being identical with the bacteriolysins, the process 

 of agglutination being interpreted as a stage preparatory to bacteri- 

 olysis. From this standpoint their formation could be viewed as 

 evidence of a protective reaction on the part of the animal body. 

 Subsequent investigations, however, have rendered this position 

 untenable. Cholera immune serum thus loses its agglutinating 

 properties after a certain length of time, even though its bacteriolytic 

 power remains in full activity. Then, again, it has been observed 

 that in typhoid fever the agglutinative and the bactericidal power 

 of the patient's serum do not necessarily run a parallel course, but 

 may actually diverge. Gengou further showed that the agglutinins 

 do not dialyze through collodium, while the lysins do, and that the 

 injection of sodium carbonate increases the bactericidal, but not the 

 agglutinative power. While the agglutinins are thus unquestionably 

 not identical with the bacteriolysins there are reasons for believing 

 that they may after all not be antibodies sui generis (see Precipitins) . 



The most important organisms with which agglutinin formation 

 has been successfully produced are the typhoid and paratyphoid 

 (A and B), the cholera and dysentery bacillus, the bacillus lactis 

 aerogenes, the diphtheria bacillus, the tubercle bacillus, the plague 

 bacillus, the bacillus of glanders, the influenza bacillus, Friedlander's 

 bacillus, the bacillus of tetanus and of rhinoscleroma, the pyocyaneus 

 and proteus bacillus, the bacillus enteritidis, the cholera vibrio, 

 the micrococcus melitensis, staphylococcus aureus, streptococcus 

 pyogenes, the pneumococcus, and the meningococcus intracellularis. 



Precipitins. Shortly after the discovery of the agglutinating power 

 of certain antisera, Kraus ascertained that such sera when brought 

 together with the clear filtrates of the corresponding bouillon cultures 

 will cause the appearance of a turbidity which gradually collects 

 at the bottom of the tube as a precipitate (1897). Further studies 

 then showed that this peculiar behavior is owing to the presence of 



