234 JOHN T. MYERS 



Maymone (1917) suggests a somewhat similar method for the 

 differentiation of B. paratyphosus A, and B. paratyphosus B based 

 on biological characteristics and the appearance of cultures on 

 lead acetate media. 



Jordan and Victor son (1917) employed a like method for B. 

 paratyphosus B, and B. paratyphosus A. Agar tubes containing 

 a small amount of lead acetate were inoculated between the me- 

 dium and the side of the tube. All typical strains of B. paraty- 

 phosus B blackened the needle track. The typical B. paraty- 

 phosus A strains produced no blackening. Kligler (1917) sug- 

 gests a simple method for the differentiation of B. paratyphosus 

 A and B, B. typhosus, and B. dysenteriae, based on a double sugar 

 medium similar to that of Russell, containing lead acetate. 



Bacterial action probably plays a role in the formation of in- 

 testinal gases. Hydrogen sulphide is always present in intes- 

 tines and is probably formed from cystin. Senator described a 

 case in which an intoxication with hydrogen sulphide of intesti- 

 nal origin occurred, but this is apparently the only case reported. 

 (Wells 1918). Hydrogen sulphide formation by bacteria may 

 be concerned in some of the conditions included in that vague 

 term, autointoxication. 



The formation of hydrogen sulphide by bacteria is also of in- 

 terest, because of the light it may throw on the metabolism of 

 bacteria. Sasati and Otsuka (1912) carried out some experi- 

 ments with a few organisms as to the formation of hydrogen 

 sulphide with cystin, taurin, sulphur, sodium, sulphate, and 

 sodium sulphite. Burger (1914) compared cystin and peptone as 

 a source of hydrogen sulphide. 



Tanner (1918) published interesting data on various sulphur 

 compounds as a source of hydrogen sulphide when acted on by 

 bacteria. He (1918) has also contributed a valuable article 

 on the formation of hydrogen sulphide by yeasts. 



