ANTISEPTICS 



167 



Fig. 34. Left: Death curve of various cocci treated with oO ppm. of 

 penicillin. Abscissa: time in hours; ordinate: logarithm of the number 

 of cells per cc. 



Right: Relation between penicillin concentration and death time of 

 Streptococcus hemolyticus. Abscissa: death time in hours, on logarith- 

 mic scale; ordinate: penicillin concentration, in ppm., on logarithmic 

 scale. (From data of Hobby, Meyer and Chaffee, 1942.) 



which took the form of unsegmented filaments ten or 

 more times longer than the average cell." Gram-nega- 

 tive rods also became greatly elongated. Vibrio comma 

 grew into immensely swollen filaments. ''With staphylo- 

 cocci, the morphological change takes the form of spher- 

 ical enlargement of the cell and imperfect fission . . . 

 Streptococcus pyogenes showed great swelling of the 

 cells, incomplete fission with formation of large spinoles, 

 and increased length of chain." Gardner concludes: 

 "Growth proceeds, but division and separation do not 

 follow in due course. Many cells then fall victim to 

 autolysis." In the experiments mentioned in Table 35, 

 the present writer observed in the streptococcus cultures 

 giant cells and rod-shaped cells, apparently due to con- 

 tinued growth in one dimension without formation of par- 

 titions, but litle change was noted in the staphylococcus 

 cultures. 



Similar morphological changes have been occasionally 

 reported for other antiseptics, e.g., for methyl violet by 

 Walker and Murray (1904) and for sulfanilamide by 

 Tunnicliff (1939). But if such effects were the rule 

 with those substances they would have been more fre- 

 quently reported. 



