ANNUAL REPORT, 1943-44 51 



One-third of the pantothenic acid in the raw fish was destroyed during baking. 

 In a 4-ounce serving of baked fish, mackerel had the largest quantity of this 

 vitamin (4.6 mg.), flounder contained 2.4 mg., and those species related to the 

 cod contained the least (1.'/ mg.). 



Dietary Factors Influencing Tooth Decay. (J. O. Holmes and L. R. Parkin- 

 son.) Massachusetts leads all other states in the incidence of tooth decay. 

 Since human experience teaches that tooth decay can be inhibited by diet, this 

 study was undertaken in an attempt to shed light on the dietary factors con- 

 cerned. Rats were used as the experimental animals. They were fed a diet 

 composed predominantly of coarsely ground corn. The hard particles cause 

 fracturing of the teeth and enamel thereby presumably providing a surface 

 susceptible to decay. In this respect the initiation of tooth decay in the rat ap- 

 parently is not comparable to that in man. In addition to the basal diet various 

 substances were fed; namely, cod-liver oil, sodium fluoride, vitamin K, the amino 

 acid, cystine, a solubilized liver fraction containing several vitamins, the filtrate 

 fraction of the vitamin-B complex containing several of the B vitamins, and the 

 following individual components of the vitamin-B complex, choline, folic acid, 

 para amino benzoic acid, biotin, pantothenic acid and inositol. Judged by the 

 number of teeth wholly or partially missing, all of the diets allowed tooth de- 

 struction. However, fewer teeth were missing in the rats fed either fluorine or 

 the filtrate fraction of the vitamin-B complex. The diet conducive to the greatest 

 destruction of the teeth was the one containing choline. Examination of the 

 teeth for small cavities has not been made as yet ; such an examination is neces- 

 sary before final conclusions can be made. 



Calcification of Eggshell. (Marie S. Gutowska and Carl A. Mitchell.) Since 

 poultrymen occasionally find soft-shell eggs, this study was undertaken to de- 

 termine the factors concerned with the deposition of calcium carbonate onto the 

 eggshell membrane. Phosphatase, the enzyme responsible for calcification of 

 bone, apparently plays no role here. Proof that the enzyme concerned is car- 

 bonic anhydrase was obtained from two sources: (1) from data showing a higher 

 content of this enzyme in the shell gland of layers than of non-layers and of layers 

 of strong-shell eggs than of layers of soft-shell eggs; (2) from data obtained by 

 injecting into laying hens sulfanilamide, which has an inhibiting effect on car- 

 bonic anhydrase activity. By varying the dosage, shells were produced with 

 varying degrees of thickness, ranging from a thin soft membrane to a thick, chalky 

 shell (see cut). The thickness of the shell varied directly with the level of car- 

 bonic anhydrase in the shell gland following the sulfanilamide injections. The 

 carbonic anhydrase in the shell gland apparently acts as a catalyst in releasing 

 from the blood carbonate ions, which, in turn, unite with the calcium of the blood 

 to form calcium carbonate. The developing egg probably does not play an active 

 role; its slight alkalinity provides a favorable environment for the precipitation 

 of the calcium carbonate onto the membrane as the egg passes through the shell 

 gland. 



