58 BIOLOGY OF PNEUMOCOCCUS 



Harkins 590 contributed the interesting but unexplained observa- 

 tion that the bile of animals in which an artificial cholecystitis had 

 been set up by intracystic injections of organisms other than 

 Pneumococcus (B. coli communior excepted), was devoid of any 

 lytic ability. The absence of this property was not due to absorp- 

 tion as shown by the fact that the addition of the infecting bac- 

 teria (S. mitts, Staphylococcus aureus, and B. coli communior) to 

 normal bile failed to rob it of this lytic action. 



Kozlowski 751 further elucidated the action of bile-solubility by 

 demonstrating that the higher unsaturated fatty acids in bile were 

 even more powerful than cholic acid. The sodium salt of one of 

 these fatty acids with an iodine number of 174, in dilutions of ap- 

 proximately 1 to 50,000, inhibited the growth of pneumococci and, 

 in a dilution of 1 to 5,000, completely killed and dissolved the cells. 

 The soaps were active in higher dilutions and in a shorter time 

 than were the corresponding salts of taurocholic and glycocholic 

 acids. Ziegler 1571 reported that the cytolytic action of sodium de- 

 hydrocholate was comparable to the action of sodium taurocholate. 



Downie, Stent, and White 327 tested the solvent action of sapo- 

 nin, cholic, dehydrocholic, dehydro-oxycholic, apocholic, and 

 desoxycholic acids, as well as a group of choleic acids which are 

 addition compounds of desoxycholic acid. Of the substances tested, 

 saponin and the sodium salts of all the bile-acids except dehydro- 

 cholic and dehydrodesoxycholic acids, brought about lysis. The 

 similarity of the action of the sodium salts of the various choleic 

 acids to that of sodium desoxycholate indicated to the authors 

 that the former owed their activity to the desoxycholic fraction. 



Ziegler 1572 found that sodium dehydrocholate and dehydrodes- 

 oxycholate would dissolve pneumococci, thus disagreeing with 

 Downie, Stent, and White, who used cultures grown on artificial 

 media. Ziegler employed strains obtained directly from infected 

 animals without any intervening cultivation. He candidly remarked 

 that his paper created more problems than it solved. 



In studying the combined action of alkaline oleates and lino- 



