VIII, B, 5 Barber: Infection of Achlya 379 



Actively motile vibrios added to the hanging drop immediately 

 clumped and became motionless. 



April 6, 12.10 p. m. Withdrew medium and added fresh of 

 the same kind. This was repeated at 7 p. m. the same day. 



April 7, 8.30 a. m. Branch 1 still living and healthy with 

 thick protoplasm. The length of the branch has nearly doubled 

 since the second day of infection. Few vibrios are present inside 

 of filament, none of them motile. 



In order to determine if the vibrios could be revived, the 

 medium was withdrawn and one substituted which contained but 

 1 part of the acid glucose broth in 8 of water. A previous test 

 had shown that vibrios multiplied freely in this fluid with active 

 motility. 



April 7, 4.45 p. m. The protoplasm in branch 1 is apparently 

 more actively motile. Few vibrios within it and these tending 

 to clump. None outside in that part of the culture. 



April 8, 8 a. m. (temperature 29°.8) . A segment in the middle 

 of branch 1, including about 0.4 of the whole length, is still 

 living with protoplasm actively motile. Withdrew medium and 

 added fresh of the same kind. 



April 8, 7 p. m. The living portions of the filament are 

 growing into the dead portions. No vibrios found inside on 

 examination with j\ oil immersion lens. 



April 9, 7 a. m. Portion of branch still alive. 



April 9, 3.30 p. m. Branch apparently dead. No vibrios 

 found inside, but are multiplying in the outside medium. 



Summary. — An infection of this filament took place, but was 

 checked apparently in response to treatment with an acid broth. 

 The filament lived four days with conditions under which non- 

 treated infected filaments have usually died within twenty-four 

 hours. The final death of the filament — like that of the con- 

 trols — was evidently due to causes other than the cholera infec- 

 tion. 



In another experiment a plainly infected filament was ap- 

 parently "cured" in the same way. In other experiments infec- 

 tion had gone so far that the vacuole of the filament was well 

 filled with actively motile vibrios. Here infection could be 

 checked, and the vibrios made to clump by acid treatment; but 

 in those filaments which survived treatment the vibrios some- 

 times became active again. In some cases acid-treated vibrios 

 inside living filaments took on monstrous forms, some becoming 

 thick spirals and some amoeboid in form while still retaining 

 their motility. In one infected filament the protoplasm of the 



