COAL-TAR AND WATER-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 
typliosum 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 3 group, are, in 
general, toxic to the Bacterium typhosum, although not so toxic as 
the correspondmg phenols. Here again, in the same series of com- 
