H. WORMALD 233 



sub-inoculation made from an inoculated control tube of the same 

 age produced turbidity within 24 hours. 



The coccus-like forms were produced consistently only in bouillon 

 containing 4 — 7 % alcohol. This morphological change cannot be 

 attributed to any action on the part of the alcohol upon the nutrient 

 constituents of the medium that would render them less assimilable 

 and it seems probable that at these concentrations the bouillon remains 

 practically unaltered as is shown by the fact that when growth at length 

 does commence (as indicated by the first signs of turbidity) it proceeds 

 approximately at the normal rate. Thus a culture with 5 % alcohol 

 first showed a very slight turbidity on the seventh day after inoculation ; 

 at the end of the succeeding 24 hours the turbidity was quite pro- 

 nounced and there was a little sediment, this being the condition 

 assumed by a tube of normal bouillon 24 hours after inoculation. 

 Microscopic examination of a drop of the turbid liquid of this culture 

 showed the bacillus in the form of cocci even at this early stage of its 

 development when food-stuffs must have been abundant. Two 

 "poured plates" were prepared from this culture; one produced 

 numerous minute colonies in which the individuals were again coccus- 

 like, the other gave rise to five colonies each of which was examined 

 and found to consist of the bacilliform motile rods. Assuming that 

 no contamination had occurred it would appear that when the coccus- 

 forms are sown thickly so that continued multiplication is arrested 

 at a comparatively early stage that form is retained, while when they 

 are fewer in number growth continues for a longer time and they 

 revert to their normal shape and size. The experiment was repeated 

 using another tube of bouillon containing 5 % alcohol with similar 

 results ; in 48 hours the plate in which the cocci had been sown thickly 

 had very numerous minute colonies of coccus-forms, while the other 

 had well-isolated colonies (though fairly numerous) up to 2-5 mm. 

 in diameter and these consisted of typical rods. 



Alcohol is well known to have dehydrating properties and it may 

 be that its presence in the culture solution creates a condition of 

 physiological desiccation which at first inhibits growth altogether. 

 The isodiametric forms induced by the alcohol are probably more 

 resistant to its action than the normal rods^ since they offer a smaller 

 surface to its dehydrating influence. 



The shape and size of these coccus-like forms may conveniently be 

 demonstrated by preparing a smear on a cover-glass in the usual way 

 with a drop of the bouillon containing them ; after drying and fixing 



