UEAt Tiox OF cur/rruE media. 



351 



Tai!le 7. — Chdiigefi in morpholo(/ij in a typical cholera vihrio from O.o per cent 

 alkaline peptone first transferred to 2.5 per cent alkaline peptone for various 

 periods of time and then to 0.3 per cent acid peptone, aiul to l.O per cent acid 

 agar. 



Genera- 

 tion. 



Morphology when transferred to \ 

 2. b per cent alkaline peptone. i 



) 



Morphology when 

 transferred to 0. 3 per 



Morphology when 

 transferred to 1 per 



Transfered. 



Left standing. 



cent acid peptone. 



cent acid agar. | 



First. 



Spherical forms 



1 

 After 10 days, ty- [ 



Spherical or oval 

 form, very few 





/Mostlycocci.afew, 





first day. 



pical forms. i 





oval forms. 











curved. 









Second . 



Oval forms, lirst 



After 8 days, typi- 



Spheres or oval 



i 



i Spherical or oval 







day. 



cal. 



and thick forms. 



a 



a. 

 o 

 "3 



t> 



0) 



forms, a few 

 curved rod 

 forms. 



5 



g 

 bo 



Third- 



Oval rods, first 



After 6 days, typi- ; 



Spheres or oval 



■o 



Few spherical 



^ 





day. 



cal forms. 



and thick forms. 





forms, oval and 

 rods forms. 





Fourth _ 



Curved rods, four- 

 t e e n t h day 



After 4 days, typi- 

 cal forms. 



Few spherical 

 forms, mostly 



o 



s 



O 



Oval and rod forms 

 some curved 



3 





from the first 





curved short 



fC 



forms. 







generation. 





forms. 



< 







Fifth ._. 



Typical forms, fif- 



After 2 days, typi- 



Mostly curved 





Rods most of them 







teenth day 



cal forms. 



forms, a few ova^ 

 or rod forms. ' 





\ curved. ' 



1 





from the first 











generation. 









From Table 7 it may be seen tliat all the strains of the cholera vibrio 

 show variations in morphology in the culture media of different reaction, 

 and tliat each has no constant form in any one culture medium until 

 after its adaption to that medium has become complete. After the 

 cholera vibrio has become adapted to media of high alkalinity or high 

 acidity and grows in typical form in such media, if it is then tran- 

 splanted to media of a neutral reaction, it assumes an atypical or 

 spherical form. This variability in the morphology of the cholera 

 vibrio seems to justify the employment of three jjeptoiie sohitions of 

 different reaction for the routine technique in the isolation of this 

 organism. 1 do not claim that the reaction of tlie culture inediuin is 

 the only factor that gives rise to pleomorpliism in the cholera vibrio: 

 there are probably other factors whicli also do this and this (nicstiou 

 should be investigated further. 



No relationship between the production of indol on the one band 

 and the i-eaction of tlie culture medium and the morpliology of the 

 cholera organism on the other could be estai)lisbcd. (See Tables 8 

 and 9.) For ibis reason the indol reaction is not of great assistance 

 in tlic diagnosis of the cholera vibi'io. 



91670 4 



