5o6 CURRENT PROBLEMS ON YEASTS 



the view that either acetaldehyde or pyruvic acid was an intermediate stage between 

 the hexose molecule or the fatty acid. Maclean and Hoffert believed that the acetal- 

 dehyde was first condensed to hexose, and that this was either converted into stored 

 carbohydrate or directly condensed to form the higher fatty acids without passing 

 through a fatty aldehyde stage, probably by a direct linking of hexose molecules. 



Lindner and Unger'-^ observed fat formation in many of the common yeasts 

 when exposed to an atmosphere of ethyl alcohol. 



Studies on the fat content of yeast have not been without practical application. 

 A German patent (No. 320560; April 4, 1920) describes a yeast which ordinarily con- 

 tains 5 per cent of fat but which, when grown in sugar-mineral salt mixtures in the 

 presence of air, increases its amount of fat to from 40 to 50 per cent. 



Haehn-5 stated that ability to form fat was a vital process of the cell and that it 

 disappeared when the cell was destroyed. This work was continued in collaboration 

 with Kin toff.'' Acetaldehyde was suggested as an intermediate product in the con- 

 version of carbohydrates into fats in living cells. The following scheme was suggested: 



Dextrose --> Pyruvic-^* Acetaldehyde ->A1 do) -» Glycerol 

 acid ester 



Haehn and Kintoff were able to produce evidence that several of these intermediate 

 products were formed. 



USE OF YEAST IN THERAPEUTICS 



Different kinds of yeast have been used for ages in the treatment of disease. We 

 are told that the monks used yeast for the treatment of plague and that Hippocrates 

 advised its use in leukorrhea. It has been stated that the administration of brewery 

 yeast^ gave beneficial results in cases of boils, anthrax, and skin infections. It was 

 also used as a lotion or injection for malignant discharges. Present-day interest in the 

 therapeutic use of yeast probably began with the publication of Hawk, Knowles, 

 Rehfuss, and Clarke.'' They used Fleischmann's pressed yeast and found it to be a 

 useful remedy in the treatment of furunculosis, acne vulgaris, acne rosacea, constipa- 

 tion, and certain other cutaneous and gastro-intestinal conditions. Only one of seven- 

 teen cases of furunculosis was not benefited by the yeast treatment; all of the cases 

 (seventeen) of acne vulgaris were improved. All of the eight cases of acne rosacea 

 were improved. Nine out of ten cases of constipation were cured or improved. It was 

 also stated that the yeast treatment was followed by an improvement in the gen- 

 eral physical condition of the patient quite unassociated with the improvement of the 

 symptoms associated with the disease treated. Hawk and his colleagues stated that 

 killed yeast was just as efficacious as a laxative as living yeast, an observation not 

 confirmed by later students of the question (Murlin and Mattill). These experiments 

 were, j)erhaps, not sufficiently controlled to justify the sweeping conclusions. The 



'Lindner, P., and Unger, T.: ibid., No. i. 1919. Chem. Absls., 14, 1354. 1920. 



^Lindner, P.: Ztschr.f. ang. Chem., 35, 110-14. 1922. 



3 Haehn, H.: Zlsclir.f. tech. Biol., g, 217-24. 1921. 



-I Haehn, H., and Kintoff, W.: Berichte, 56, 439-45. 1923; Wcltiisr/i. Bran., 42, 213. 1925. 



^Wchnschr. Bran., 17, 207-8. 1900. 



''Hawk, P. B., Knowles, F. C, Rehfuss, M. Iv, and Ckiri<.e, J. A.: J.A.M.A., 69, 1243-47. 1917. 



