174 MUTATIONS 



Glass: I don't remember for what it was proposed to be used. 



Lederberg: To kill viruses. 



Glass: Yes, to kill hepatitis virus, I believe it was. This, of course, 

 is known to be one of the most potent chromosome-breaking agents 

 that has been worked with in plants, and our studies with tissue culture 

 show that it breaks primate chromosomes just as readily as it breaks 

 plant chromosomes. 



Freese: It is very mutagenic in bacteria. 



Auerbach: It also has a curious property which the ICI people 

 found. It is one of the very few substances that are carcinogenic 

 but not carcinostatic. 



Atwood: That was to be added to bank blood to prevent the spread 

 of serum hepatitis. There wouldn't be a residual if it were added. 



Goldstein: I want to mention nicotine, and I will come back to it 

 again. It has been shown to cause chromosome damage in plants (5), 

 and, of course, there is wide exposure of the human population. We 

 also have an example of an acridine-type compound which has had 

 wide use in medicine — quinacrine (also known as atabrine), which 

 was for long the mainstay of antimalarial therapy and prophylaxis. 

 Some acridines are certainly mutagenic (5), but I am not aware of 

 any evidence that this particular one is. 



Finally, I should like to point out that many steroids are used 

 medicinally (e.g., the digitalis group and the adrenal cortical steroids) 

 and that some steroids are strong mitotic poisons (5). I shall discuss 

 later a particular steroid which is proposed for very widespread use as 

 an oral contraceptive agent. 



I have not listed any of the purine analogues here because I expect 

 to talk about caffeine and related compounds at length. 



The purpose of this enumeration was not to make any special point, 

 but only to indicate that compounds known to be mutagens or chromo- 

 some breakers, and closely related compounds, are used widely in medi- 

 cine, and no one has yet given much attention to the question whether 

 or not they may be genetic hazards. 



Auerbach: May I raise a general question which I would like to 

 have discussed, if somebody has evidence on it? On going through the 

 literature, I got the impression that plant chromosomes have a much 

 more easily disturbed structural stability than animal chromosomes. 

 I don't know whether there is any evidence from tissue culture. Anoxia, 

 too much oxygen, or too little oxygen, aging — all these conditions 

 seem to produce chromosome breaks in plant cells. 



Auerbach: In tissue culture? 



