108 MORPHOLOGIC VARIATION 



measured), which are given in Table XXI. The coefficient is 

 high when the granules are numerous, low when they are scarce. 

 This is probably a spurious correlation; the two values happen to 

 move together during part of the growth cycle, but are not actually 

 related. 



While one cannot clearly establish the relationship between the 

 morphologic variations of this organisms and the phases of growth 

 from the data at hand, it can be readily demonstrated that these 

 variations are dependent upon the rate of growth by observing the 

 effect of varying the size of the seeding and the concentration of 

 nutrients in the medium. This has not been done quantitatively, 

 but the drawings in Figure 30 show the effect. These were made 

 from cultures on dextrose agar (dextrose 5 per cent, peptone 1 per 

 cent) inoculated from a twenty-four-hour old culture on the same 

 medium, the cells of which are illustrated in the drawing marked 

 hour. Three series were run in parallel. The two marked "Heavy 

 inoculum" were seeded with the same number of cells; that marked 

 "Light inoculum" received one-tenth as many. The two marked 

 "Full strength medium" were inoculated onto agar slants having 

 the composition given above; the one marked "Dilute medium" was 

 planted onto agar slants having just one-fourth as much dextrose 

 and peptone. It will be seen that in the dilute medium the morpho- 

 logic variations were not so pronounced as in the full strength, and 

 that with a light seeding there was more variation than with the 

 larger inoculum. Those conditions which lead to a high growth 

 rate, viz., small seeding and large concentration of nutrients, cause 

 a development of more of the small, intensely stained, granule-free 

 cells and their persistence for a longer period of time. This being 

 the case, it is probable that these small cells are truly to be con- 

 sidered the form characteristic of the growth period rather than 

 the resting phase, that they are the embryonic forms of this type 

 of organism, and the failure of the curves to correlate in phase in 

 Figure 28 is really due to some experimental error. 



It is rather striking in these drawings that the small forms be- 

 come almost spherical and are arranged in chains; this is especially 

 evident in the light inoculum, full strength medium. At ten and 

 fifteen hours the cells would hardly be recognized as being related 



