XI. PATHOLOGY 489 



reversed by vitamin Bi:. Xo attempt was made to remove hydrogen per- 

 oxide from the reaction mixtures before testing on L. Icichamnnnii 4797, 

 and according to the description of the procedure significant ciuantities of 

 hydrogen peroxide were evidently added to the growth tubes. This is par- 

 ticularly important, since Koditschek ct al? have shown that as little as 

 10 7 of hydrogen peroxide per milliliter would completely inhibit L. lacHs 

 8000 and that smaller amounts gave readily measurable inhibition. This 

 inhibition by hydrogen peroxide, moreover, was competitively reversed by 

 \ itamin Bij over a considerable range of concentration. Until demonstrated 

 to the contrary it appears quite likely that the inhibition observed by 

 Beiler el a/.'" was due to residual hydrogen peroxide. 



Studying microorganisms which re([uire vitamin B12, Hendlin and Soars*' 

 have found that 1 .2-dimethyl-4,5-diaminobenzene is inhibitory and that 

 it could be reversed b\' vitamin B12. The toxic properties of 5,6-dimethyl- 

 l)enzimidazole and its analogs were not reversed V)y vitamin Bio. From the 

 observation of Emerson </ o/.''^ that dimethyldiaminobenzene possessed 

 \itamin Bij activity for the rat when fed in the diet and from WooUey's 

 demonstration-®' -^ on the precursor role of this compound, it would ap- 

 pear that the animal activity of this compound is due to conversion to 

 vitamin B12 by the intestinal flora. As Hendlin and Soars point out,'- an 

 alternate possibility is that, since dimethyldiaminobenzene is toxic to vi- 

 tamin Bi2-requiring organisms, such organisms are inhibited in the intesti- 

 nal tract, allowing more vitamin B12 to become available to the animal. 



XI. Pathology 

 A. CHICKS 



THOMAS H. JUKES and WILLIAM L. WILLIAMS 



A numl)er of specific deformities have been described in chick embryos 

 developing in eggs laid by hens on deficient diets. A diminution in hatch- 

 ability was noted as the soybean meal content of the diet of hens was raised 

 from to 40% of the diet.^ 



The effect was reversed when cow manure was added to the diet.- Further 

 investigations' were made with the basal diet containing 30 % sovl)ean meal, 

 and, of 104 embryos examined, 12 had d\^strophic leg muscles without 



32 D. Hendlin and M. H. Soars, J. Bacteriol. 62, 633 (1951). 



" G. Emerson, N. G. Brink, F. W. Hally, F. Koniuszy, D. Heyl, and K. Folknra 



J. Am. Chem. Soc. 72, 3084 (1950). 

 ' D. Wl.itson, H. W. Titus, and H. R. Bird, Poultry Sci . 25, 52 (1946). 



2 D. Whitson, H. W. Titus, and H. R. Bird, PoiiHry Sci. 25, 143 (1946). 



3 H. R. Bird, M. Rubin, D. Whitson, and S. K. Haynes, Poultry ScL 25, 285 (1946). 



