Nutrition of Bacteria. 



197 



by the presence, of the added potassium phosphate; but this does 

 not imply that in these cases the cause of rickets was necessarily 

 a deficiency either of potassium or of phosphorus. The quanti- 

 tative relations of the inorganic ions rather than an absolute 

 deficiency of any one of them, may have been the determining 

 factor. Also it may well be that under certain dietary conditions, 

 rickets may be caused by deficiencies or unbalanced quantitative 

 relationships of organic as well as inorganic food factors. It would 

 appear however to have been demonstrated that rickets may be 

 caused or prevented without change in either the protein or vita- 

 min components of the diet and therefore that neither of these 

 can be regarded as a necessarily predominating factor. It is also 

 of outstanding interest that the rats showing multiple fractures 

 and marked deformity of thorax, which would probably be in- 

 included under the classification used by some writers as "pre- 

 senting the gross picture of rickets" but whose bone lesions on 

 microscopic examination were classified as those of osteoporosis, 

 were those which had been subjected to even greater dietary 

 deficiency than those showing typical rickets. 



We are indebted to Dr. J. M. Steiner for his cooperation in the 

 X-ray examinations and to Miss F. L. MacLeod for the quantita- 

 tive determinations of calcium. 



98 (1680) 



Growth accessory substances in the nutrition of bacteria. 



By TH. THJOTTA and O. T. AVERY. 



. [From the Hospital of the Rockefeller Institute, N. Y. City.} 



In studying the growth characteristics of mucoid bacilli Thjotta 

 observed that B. influenzm will grow in blood-free broth containing 

 the mucoid material from cultures of Friedlander's bacillus and 

 other closely allied organisms. The growth accessory substance 

 or substances which can replace blood and blood derivatives in 

 the cultivation of Pfeiffer's bacillus Thjotta found in both the 

 saline suspensions and watery extracts of the heat killed bacillary 

 material. Furthermore, these bacterial emulsions and extracts 

 can be boiled for ten minutes and filtered through Berkefeld 



