33 



Several observers have found that lytic material is present in 

 the serum of an animal shortly after inoculation with a small dose 

 of bacteria. To take a recently published example, Otto, Munter, 

 and Winkler* inoculated a guinea-pig intraperitoneally with 

 one-twentieth of a loopful of Flexner bacilli and found that lytic 

 principle was present in the serum obtained by heart puncture 

 seven hours afterwards. No lytic material was present in the 

 control (serum of the same guinea-pig obtained shortly before 

 inoculation with bacilli). How is the activity of the later sample 

 of serum to be explained ? Is it due to the presence of bacterial 

 products, derived from the Flexner bacilli ? Or does it mean that 

 the bacteria produced in the animal's plasma a temporary chemico- 

 physical change (Allergie), and that this changed condition, 

 being present in the serum, was operative in vitro as a primary 

 stimulus causing a growing culture to produce lytic substance ? 



Similar phenomena have often been observed after injecting 

 animals with lysogenic bacterial extracts. Bordet and Ciuca.f 

 for example, injected a guinea-pig subcutaneously with 2 c.c. of 

 " lytic liquid " (a lysed and filtered suspension of B. coli) and 

 bled the animal seven hours afterwards. Twelve drops of the 

 serum, heated for half an hour at 56° C, prevented the growth of a 

 culture of B. coli, whereas the control serum, taken before inocula- 

 tion was ineffective. Similar results were obtained with the 

 serum of a rabbit taken from 7 to 24 hours after intravenous 

 injection with 20 c.c. of " lytic liquid." Here, again, the question 

 is whether the serum simply contained some of the original 

 lytic substance, which was still active, though highly diluted, 

 or whether the bacterial extract had modified the serum in a 

 way similar to that suggested at the end of the preceding paragraph. 



In the same article Bordet and Ciuca raise a similar problem 

 about the transmission of antibodies. It is worth quoting, though 

 not strictly apposite to the present question (transmission of 

 lytic substance). After withdrawing a little blood from a guinea- 

 pig weighing 600 grammes, they inoculated the animal sub- 

 cutaneously with 5 c.c. of an antilytic serum and bled it 32 hours 

 subsequently. The two sera thus obtained were heated at 

 56° C, and then two drops of each were tested for antilytic 

 power ; the former serum was inactive, the latter active. 



I am not prepared to offer any cut-and-dried explanation of 

 these phenomena. The main fact appears to be that bacterial 

 variants, associated with lytic change, are produced in the animal 

 body as well as in the test-tube. Whether the initial stimulus 

 which produced them is bacterial or animal, their propagation 

 depends on the bacteria themselves, i.e., on bacterial growth and 

 on the action of bacterial products. This is the point which I wish 

 to emphasise for the purpose of the subject now under discussion. 

 It would be beyond the scope of the present report to enter into 

 important collateral questions about the part played by the 

 animal body in resistance to bacterial infection. 



* Zeitschr.f. Hyg., XCVL, p. 118, 1922. 



f C.R. Soo. Biol, LXXXIV., p. 280. 29th Jan., 1922, 



