2i 8 Master Minds of Modern Science 



had sucked up blood containing the germs. Ross dis- 

 proved this, and found the real solution, but not until he 

 had wasted valuable time in testing Manson's original 

 theory. 



In his Memoirs Sir Ronald Ross relates how he tried 

 to establish the truth or otherwise of the infected-water 

 theory by taking four mosquitoes which had fed upon 

 a malarial victim and placing them in two bottles with a 

 little water. The bottles were kept in a cool place for 

 a week, at the end of which the mosquitoes were dead. In 

 addition to the bodies of the infected mosquitoes, the 

 bottles contained grubs, showing that the eggs laid by 

 the insects had been hatched. 



Now Ross made his test. After removing the bodies of 

 the mosquitoes, but not the grubs, he gave the contents 

 of the bottles to certain natives who volunteered, after a 

 full explanation of the experiment had been made to 

 them, to drink the water. " I think myself justified in 

 making this experiment, " wrote Ross, " because of the 

 vast importance a positive result would have and because 

 I have a specific in quinine always at hand." 



The result of the experiment was odd. One man 

 developed an illness which at first seemed like malaria, 

 but when his blood was examined no malarial parasites 

 were found. Two other men who drank the infected 

 water remained quite well. 



Further experiments with infected water yielded 

 negative results. In fact, that first case of intermittent 

 fever, which was a coincidence, was the only case in which 

 any after-effects followed the drinking of water exposed 

 to infected insects. 



Eventually Ross abandoned Manson's theory, so far as 

 the means of infection was concerned, and began to search 

 for other means by which the parasites within the mos- 

 quito might enter the blood of human beings — the search 

 which was to end in his brilliant discovery. 



