THE GROWTH OF MAMMALIAN TUBERCLE BACILLI IN TWEEN-ALBUMIN LIQUID MEDIUM .1. OBSERVATIONS ON THE PROPORTION OF VIABLE ORGANISMS, THE CYTOLOGY, AND THE VIRULENCE OF BACILLI AT DIFFERENT STAGES OF GROWTH OF STRAIN H37RV
Bacterial growth phases in Tween-albumin liquid medium were studied by total counts, nephelometric readings, and the estimation of total numbers converted to log values. Generation times and the relationship of the viable and total counts were detd. also. The size of the cells varies considerably at different stages of growth. Nuclear staining shows 1 to 5 or more nuclei per bacterium. Within 2 hrs. of inoculation of culture media, the number of nuclei per bacterium rises to a value of over 5 and then falls rapidly. After the 3d day, this value remains fairly constant until the 14th day. During the first few days of incubation the aggregation of the bacilli increases and then remains constant for approx. 1 week. Thereafter the bacilli become dispersed more completely. The neutral red test gives a strongly positive reaction throughout except for the period from the 18th to the 48th hrs., when the color reaction is orange rather than red. Virulence for mice, tested by intraven. inoculation, falls to a relatively low value during the first 24 hrs., rises to a high level on the 3d and 4th days, and then gradually falls to a low level at the end of the 3d week. The proportion of nonacid-fast bacilli fluctuates considerably, without any relationship to the age of the culture.