32 



had been adapted to the typhoid bacillus and had lost all action 

 on coli. The antiserum obtained from the latter neutralised not 

 only the Lou vain " bacteriophage " but also its predecessor, the 

 coli " bacteriophage " ; it had no action on the Strasburg " bac- 

 teriophage." The Strasburg antiserum neutralised only the 

 Strasburg " bacteriophage." Gratia and Namur* obtained some- 

 what similar results with antisera for substances which were 

 lytic for staphylococci. The one substance (BH) was lytic 

 primarily for Staphylococcus aureus (H) and the other (BV) for 

 Staphylococcus albus (V) ; but, whereas BH acted on many strains 

 of these organisms, including V, BV was strictly specific for V. 

 The antiserum prepared with BH was specific for BH alone and 

 the antiserum for BV was equally selective for BV. After the 

 lytic principle BH had baen allowed to act on V and had been 

 transmitted ten times through V, the action of the two antisera 

 was tested on the lytic substance finally obtained. It was found 

 that no change had taken place ; specific neutralisation was still 

 obtained by the BH antiserum but not by the BV antiserum. 



How do these antilytic sera act ? Do they behave like 

 ordinary antibodies which combine with specific constituents 

 corresponding to those of the antigen used for immunisation ? 

 Apparently they do ; at least, there is no reason to suppose that 

 they are an exception to the ordinary rule. In this connection 

 the following absorption experiments are worth noting. Jaumain 

 and Meulemanf placed in each of three tubes 5 c.c. of a lytic 

 principle active for staphylococci and added to tube (a) 10 drops 

 of broth, to (6) a like quantity of coli culture killed by heat, and 

 to (c) the same amount of staphylococci killed in the same way. 

 The tubes were sealed and kept in the incubator for three days. 

 Then the contents were tested quantitatively for lytic action on 

 staphylococci ; (a) and (b) had lost none of their activity, but 

 (c) was 1,000 times weaker. A few days later, filtrates from the 

 three tubes were tested ; (a) and (6) were as potent as the original ; 

 (c) was inactive. They stated that similar results, viz., absorption 

 of active principle by killed homologous bacteria, had been 

 obtained by Costa Cruz with B. coli. This absorption, they 

 found, was strictly specific and was not obtained if the killed 

 bacteria, though belonging to the same species, were derived from 

 a strain not sensitive to the lytic principle. 



I mentioned above (p. 21) that it is convenient to draw a 

 distinction between the initial stimulus, which starts the produc- 

 tion of transmissible lytic material, and this material itself. 

 The former may be some non-specific chemical or physical 

 influence ; the latter is definitely a bacterial product. This 

 distinction is worth bearing in mind when one comes to consider 

 the significance of the lytic material which is obtained not from 

 the test-tube but from the animal body. 



* C.R. Soc. Biol, LXXXVIL, p. 364. 24th June, 1^22. 

 f C.R. Soc. Biol, LXXXVIL, p. 362. 24th June, 1922. 



