On the Growth Requirements of Pneumococci

Conclusions A simplified medium has been described which supported the growth of 26 out of 29 strains of pneumococci. All strains required biotin, choline, nicotinic acid, and pantothenic acid for growth, but varied in their response to thiamin, asparagine, adenine, guanine, and uracil. The extent of this variation makes apparent the necessity of considering the growth requirements of each strain in the study of pneumococcal nutrition. In such a study the importance of concentration and interaction of medium constituents, size of inoculum, and the time of measurement of growth cannot be overemphasized.