Weight Increments of Premature Infants. 133 



made at the same time. In agar cultures inoculated from a 

 12-hour agar culture (which has nearly reached the maximum of 

 growth but has not yet formed spores) it was found that the 

 cells began to increase in size during the lag phase and reached a 

 maximum length, about six times that of the inoculated cells, 

 shortly after the beginning of the maximum growth phase, then 

 rapidly becoming shorter. During the period of increase in length, 

 frequency curves showed a tendency towards bi modality, indicat- 

 ing that possibly a process of selection of rapidly growing cells 

 may occur during the lag phase, as has been suggested by some 

 investigators. 



Two series of broth cultures inoculated from a 7-hour agar 

 culture (during the period of maximum growth) showed no lag 

 phase ; nevertheless an increase in the size of the cells was observed 

 beginning two hours after inoculation. The cells did not become 

 so large as did those on agar, and the variation was not so great, 

 bimodality being present in but one of the frequency curves. 

 One series was inoculated with 10 times as many bacteria as the 

 other, and the series receiving the lesser amount of inoculum 

 showed a slightly greater increase in the size of the cells over a 

 slightly longer period of time. 



67 (1814) 



On the weight increments of premature infants as compared with 

 those of fetuses of the same gestation age and those of 

 full-term children. 



By RICHARD E. SCAMMON. 



[From the Department of Anatomy, University of Minnesota, 

 Minneapolis, Minn.] 



One method of approaching the problem of the effect of birth 

 and the postnatal environment on the course of human growth is 

 by the comparison of the rates of growth of premature infants 

 with the growth rates of fetuses of the same gestation age and 

 with those of full-term children. If the environmental factors 

 are the all-important ones it might be expected a priori that the 

 rate of growth of prematures would agree, in the main, with that 



