ZINSSER AND MUELLER 



727 



tion which might be adapted to further studies on bacterial products available in smaller 

 quantities. Since the work was undertaken before the publication of Heidelberger and 

 Avery's work, the widely differing chemical properties of these substances could not be 

 predicted. It was found that the specific substance of the yeast cell was apparently identical 

 with the "yeast gum" on which many studies had been made without any appreciation of 

 its relation to immunological phenomena. The fact that it was precipitable by alkaline 

 copper solutions facilitated its separation, and further purification was obtained by fractional 

 alcohol precipitation. 



Laidlaw and Dudley^ in 1925 described a specific gum prepared from ground tubercle 

 bacilli by extraction and removal of proteins, etc. A substance with such similar properties 

 as to make it reasonably sure that it represented the same material was obtained by one of 

 us^ in 1926, from concentrated broth cultures of the tubercle bacillus. The purification of 

 this material is rendered more difficult by the fact that it seems to form no insoluble com- 

 pounds of suitable nature. A considerable proportion of pentose appears to be present in 

 the gum, the remaining fraction being thus far unidentified. 



From an unclassified strain of the Friedlander bacillus a gum similar to those already 

 described was prepared by Mueller, Smith, and Litarczek,-5 using both broth cultures and 

 mass cultures on agar. A high degree of purity was not reached, but a specific precipitation 

 reaction appeared in a dilution of 1-1,000,000. 



Heidelberger, Goebel, and Avery* obtained the specific substance from a type II strain 

 of the Friedlander bacillus in a high degree of purity. Glucose formed a considerable propor- 

 tion of its hydrolytic products, and in this and other respects it presented certain points of 

 similarity to the material obtained from type II pneumococcus, the immunological and 

 chemical similarities coinciding. 



Extracts containing the soluble specific substances of streptococci, both hemolytic and 

 non-hemolytic, have been prepared by Hitchcock,^ and Lancefield,^ and Zinsser and Tamiya.^ 

 The hemolytic strains were apparently homogeneous as regards the specificity of their soluble 

 product, while the non-hemolytic strains were heterogeneous. 



Zinsser and Parker in their original contribution worked with extracts of Staphylococcus 



pyogenes aureus, B. typhosus, and B. influenzae, in addition to the pneumococcus and tubercle 



bacillus. Mueller, Wayman, and Zinsser^ included also the meningococcus among others 



already described. Przesmycki' obtained evidence that similar substances from four type 



strains of meningococci were here, as in the pneumococcus group, the bearers of type 



specificity. 



« 



It thus appears that every species of micro-organism so far examined produces as 



a part of its normal metabolism a substance highly characteristic of itself and even 



differing widely from type to type within the same species. These materials, referred 



' Laidlaw, P. P., and Dudley, H. W.: Brit. J. Exper. Path., 6, 197. 1925. 



= Mueller, J. H.: J. Exper. Med., 43, 9. 1926. 



3 Mueller, J. H., Smith, D., and Litarczek, S. : Proc. Soc. Exper. Biol, b' Med., 22, 373. 1925. 



f Heidelberger, M., Goebel, W., and Avery, O. T.: J. Exper. Med., 42, 701 and 727. 1925. 



5 Hitchcock, C. H. : ibid., 40, 445 and 575. 1924. 



'Lancefield, R. C: loc. cit. 



7 Zinsser, H., and Tamiya, T.: ibid., 42, 311. 1925. 



* Mueller, J. H., Wayman, M., and Zinsser, H.: Proc. Soc. Exper. Biol. &" Med., 21, 241. 1924. 



' Przesmycki, F.: /. Infect. Dis., 35, 537. 1924. 



