COAL-TAR AND WATEK-GAS TAR CREOSOTES. 69 



Of the tar acids and other oxygenated compounds found in coal- 

 tar creosote, perhaps the best known is phenol, or carbolic acid. 

 Phenol is recognized in medicine as being extremely toxic to practi- 

 cally all kinds of living organisms. It is used as a standard in the 

 determination of the killing power of antiseptics and bactericides. 

 The higher homologues of phenol, the cresols, are from two to four 

 times as effective toward bacteria as is phenol, and the naphthols are 

 also extremely toxic compounds which have been used as anti- 

 septics and germicides. Weiss (31) has shown that the tar acids 

 (all the tar acids extracted with caustic soda) are about as toxic as 

 pure carbolic acid to penicillium, bacteria, and yeast, and that pure 

 cresol is much stronger, requiring only a trace, whereas pure carbolic 

 acid requires 0.15 per cent. Trillat (35) in 1892 mentioned phenol 

 and alpha and beta naphthol as powerful antiseptics. Adiasiewietsch 

 (36), in 1897, in experimenting with petroleum products, added tar 

 acids among other things to increase the utilization of petroleum for 

 wood preservation. Bokany (37) compared the efficiency of phenol 

 with other antiseptics, and Schneider (38) has prepared powerful 

 antiseptics from the alpha and beta naphthols as well as from the 

 cresols. Russell and Pendleton (32) have shown that both the 

 phenols and cresols are valuable for soil sterilization, although these 

 operators found certain bacteria which apparently lived upon them. 

 Morgan and Cooper (39), in 1912, showed that against the Bacterium 

 typhosum the tar acids in general increase in toxicity with increase 

 in molecular weight; and that in the same series of compounds, an 

 increase in molecular weight is always accompanied by a rise in 

 boiling point. They also show that the dihydroxynaphthalenes 

 (2, 3, hydroxynaphthalenes and 2, 7, hydroxynaphthalenes) , that is, 

 naphthols having two phenolic groups, are between three and five 

 times as toxic as phenols. It will be noted that the references given 

 here are to comparatively recent experiments, some of which were 

 directly connected with the wood-preserving industries. The refer- 

 ences have been given to show that there are a number of investi- 

 gators in wood preservatives who believe that coal-tar creosote owes 

 its antiseptic properties, in a large measure at least, to phenols or 

 tar acids. 



The nitrogen bodies, that is, the pyridines, quinolines, and some 

 others, have not been investigated so thoroughly as the phenols. 

 Trillat (35) placed both quinoline and pyridine in the list of powerful 

 antiseptics. Weiss (31) has shown that quinoline has decided anti- 

 septic properties, being somewhat stronger than the phenols against 

 the organisms tested. Morgan and Cooper (39) showed that the 

 amines, that is, those compounds containing an NH^ group, are, in 

 general, toxic to the Bacterium typhosum, although not so toxic as 

 the corresponding phenols. Here again, in the same series of com- 



