jf. B. S. Haldane 109 



Sitting in an airtight room and so increasing the amount 

 of carbonic acid in the blood was one way ; this ended in 

 a very bad headache, but the result was only temporary, 

 and Mr Haldane wanted something which would keep 

 him acid for several days at a time. The obvious 

 method was to drink a large quantity of hydrochloric acid, 

 but hydrochloric acid is a violent poison ; taken pure, it 

 will not only burn out one's inside, but actually dissolve 

 one's teeth. The strongest solution that can safely be 

 taken is one part in one hundred of water, and even a 

 pint of that is too stiff a dose for most people. 



After considering the matter our experimenter decided 

 upon eating a quantity of ammonium chloride, which 

 would break up inside the body, liberating hydrochloric 

 acid. He took an ounce a day for two or three days, and 

 after this, he remarks casually, he remained breathless for 

 another two or three. His blood lost ten per cent, of its 

 volume, his weight dropped seven pounds in three days, 

 and his liver went very wrong. This experiment, which 

 Mr Haldane has described in a paper entitled " On being 

 One's Own Rabbit," had valuable results, for since it 

 was carried out babies suffering from tetany have been 

 given small doses of ammonium chloride, and the trouble 

 can then be cleared up within a few hours. 



We have described these experiments at some length 

 because it is worth while to point out that bio-chemists 

 do not depend upon animals for the testing of their new 

 theories, but are constantly making tests upon them- 

 selves. You may possibly have heard of the so-called 

 ' Poison Squad ' at the Federal Bureau of Chemistry in 

 Washington, U.S.A. It consists of volunteers — all expert 

 chemists — who test various adulterated food products 

 seized by Government agents, and eat them under the 

 inspection of doctors who are experts in toxicology (the 

 science of poisons). More than one of this devoted band 

 has become seriously ill, and one, Robert Vance Freeman, 



