VIII, B, 5 Barber: Infection of Achlya 377 



on a yellowish brown color and contrasts sharply with the sur- 

 rounding healthy portion. The bacteria which burst out are 

 in part living and may contaminate the medium. 



Bacillus pyocyaneus is more rapidly destructive of the fungus 

 than any other organism tested. The death of the infected 

 filament may be delayed some days by keeping at refrigerator 

 temperature, but the bacteria remain living and multiply on 

 removal to a higher temperature. 



Specific rabbit serum, agglutinating Bacillus pyocyaneus in 

 a dilution of at least 1 to 200, immediately clumped bacilli outside 

 the filaments, but had no effect on those inside, even in dead 

 filaments where the cellulose wall of the host alone intervened 

 between, the serum and bacilli. Undiluted serum was discharged 

 from a pipette against such walls with no eff'ect on the motility 

 of bacteria inside. This serum had no immediately harmful 

 effect on healthy Achlya filaments. 



Inoculation with the vibrios of Asiatic cholera gave results 

 similar to those with Bacillus pyocyaneus, except that infection 

 was less sure and proceeded more slowly. The contents of 

 Achlya cells are evidently a favorable medium for the growth of 

 cholera. This is shown not only by successful infection, but by 

 the fact that vibrios lying outside are immediately attracted to 

 a spot where the pricking of a hypha has allowed cell contents to 

 escape. 



An infected hypha after death became packed with vibrios 

 in much the same way as with Bacillus pyocyaneus, and similar 

 extrusions from burst places occurred, but less strikingly than 

 in the case of Bacillus pyocyaneus. (Plate II.) Some 10 suc- 

 cessful inoculations were made with cholera, all in Achlya culti- 

 vated in artificial media. 



The experiments with agglutinating serum were repeated with 

 cholera. Infected hyphse, both dead and living, were treated with 

 a rabbit serum agglutinating in a dilution of at least 1:500. 

 Any vibrios outside were immediately clumped; but, as in the 

 case of Bacillus pyocyaneus, the cellulose wall appeared to be 

 an effective barrier against the passage of the agglutinins. In 

 one experiment, a one-half dilution of the strongly agglutinating 

 serum was injected directly into an infected hypha by means of a 

 fine capillary pipette. The vibrios inside were immediately agglu- 

 tinated, although they had been unaffected by the same dilution 

 applied outside. The serum-injected hypha lived for at least 

 three-fourths of an hour after the inoculation, as shown by the 

 movement of its protoplasm. Infected cells, even though living 

 and with actively motile protoplasm, had a diminished turgidity ; 



