34 Inside the Living Cell 



that there was a clear patch around a growth of the fungus on a 

 plate on which colonies of bacteria were growing. He recognized that 

 the fungus was producing a substance which prevented the growth 

 of the bacteria. The isolation and identification of this substance, as 

 the result first of the efforts of a group of workers headed by Sir 

 Howard Florey and Professor Chain in Oxford and the co-operative 

 effort of scientists on both sides of the Atlantic during the 1939-45 

 war, and its large-scale production and use in medicine have been 

 one of the greatest triumphs of intensive research. Penicillin is unique 

 in having an extremely powerful effect on some types of bacteria and 

 in doing no harm to animals, and is one of the most powerful means 

 of combating many kinds of bacteria which is available at the present 

 time. The nature of its action is not clearly understood. 



But many other 'antibiotics', as they are called, have also been 

 discovered in recent years. Many of them are too harmful to human 

 beings to find use in medicine. Others, like gramicidin, and strepto- 

 mycin, both prepared from soil bacteria, are extremely useful. 



Streptomycin, which is produced by a micro-organism first isolated 

 from the soil of a field near Caracas in Venezuela, seems to be 

 effective in some cases of tuberculosis. This family of micro- 

 organisms (Streptomyces) — in this case a type isolated from a com- 

 post heap in Illinois — has also yielded Chloromycetin, which has 

 been found to be a most successful curative agent for typhus — a 

 louse-carried fever which is common in overcrowded conditions in 

 the tropics. It almost completely fulfils the two requirements of an 

 effective drug — it is deadly against the agent of the disease, and 

 harmless to the human body. Although it is also effective against 

 some bacteria, it is of great interest because typhus is a virus disease 

 and this is the first drug to be discovered which is effective in such 

 cases. Virus diseases have hitherto been very refractory to treatment 

 by chemical agents, so that this discovery opens up great possibilities 

 of new treatments. Chloromycetin has been found to be a compara- 

 tively simple compound and has been synthesized. Another useful 

 agent of the same type is known as aureomycin or duomycin, which 

 is very effective in rocky mountain fever and other virus diseases of 

 the same type. 



All these substances may be similar to fragments of proteins — 

 probably warped fragments, which will not fit into the normal protein 

 molecule. 



Competition in the world of micro-organisms, which multiply at a 

 very rapid rate, must be very intense, and any species which can 

 produce something which kills, or merely prevents the multiplication 

 of, organisms in its neighbourhood, secures for itself the chance to 



