214 Microbes and You 



BACTERIOSTATIC AND BACTERICIDAL ACTION OF DYES 



Many dyes employed in industry today contain aniline, a sub- 

 stance which can be treated in various ways to create stable pig- 

 ments. Some of these dyes adversely affect microbial protoplasm, 

 and they can be incorporated into selective media for retarding 

 the growth of specific organisms. Often a given concentration of 

 a specific dye will inhibit bacterial growth, while a higher con- 

 centration of that same dye may kill the organisms. There is a 

 relationship between the gram staining reaction and the effect of 

 the dyes. Medicine takes advantage of the action of gentian 

 violet in the treatment of wounds, burns, and some skin infections. 



DENTIFRICES 



The published claims and the true merits of dentifrices are an 

 interesting subject for extensive investigation, but here only the 

 highlights of the topic are discussed. 



If we knew with finality the cause of tooth decay, undoubtedly 

 drastic changes in our way of living might be warranted. But 

 since all available evidence points to a multiplicity of causes for 

 this human affliction, man attempts to treat the condition from a 

 number of standpoints. Lower animals do not experience the 

 extensive tooth troubles affecting man. What do these lower 

 animals do that is different? 



Nutritionists have demonstrated that at least part of tooth decay 

 can be attributed to diet. Perhaps poor nutrition is the primary 

 cause of dental caries and other factors stem from this original 

 weakness in tooth structure. Since calcium and phosphorus, 

 among other elements, make up the chemical composition of our 

 teeth, it is logical to assume that if these vital elements are lacking 

 in our diet, their shortage will be reffected in poor tooth structure 

 and in ultimate decay. 



Millions, even billions, of viable bacteria can be found in a 

 human mouth, and the varied species that can be isolated present 

 an interesting field for study. We know that among other end 

 products of bacterial metabolism, acids are formed, and the amount 



