48 RELATIONSHIPS OF THE COCCACE^l 



recorded on the first, second, seventh, fourteenth, forty- 

 second days and after two months, respectively. The 

 largest cells appeared indiscriminately in broth at 37 

 degrees, in broth at 20 degrees, on Nahrstoff-Heyden, 

 nutrient gelatin, acid and alkalin gelatin, and under 

 anaerobic conditions. In other words, the age and kind 

 of medium had no constant effect, except that in 

 most cases the Nahrstoff and other poor media showed 

 the smallest individuals. These results are not in 

 harmony with those of other observers. Neisser and 

 Lipstein (1903) state that unfavorable conditions, such 

 as excessively high temperatures, and acidity or extreme 

 alkalinity of the medium, tend to produce large cells; 

 and the same thing has been noted in old cultures 

 by other authors. It might naturally be expected that 

 cells would be smaller in rapidly growing cultures than 

 in those in which development had been checked. 

 In our investigations, however, no constant difference 

 in size was apparent in young and old cultures, on solid 

 and in liquid media. One series of organisms examined 

 in dextrose broth and on agar, at periods ranging 

 from one day to two weeks, showed the same average 

 size in both media and at all ages. Finally, we attempted 

 to see whether prolonged cultivation under special con- 

 ditions would affect the size of the cell. Cultures were 

 grown for ten days in broth at 37 degrees, on nutrient 

 gelatin at 20 degrees, and on acid and anaerobic gelatin, 

 with daily transfers. The size of each culture was 



