23,5 Leach et al.: Hookworm Infestation 467 



to some concomitant condition of another nature, and possibly 

 from a different location. This is not a quibble ; it is very ger- 

 mane. In view of the frequent pathology found in tropical 

 livers, we consider this a very important point to determine. 

 Interpretation of such findings should be made with strict at- 

 tention to the fallacy of concomitant variations. 



In our judgment, it will require more complete and convin- 

 cing evidence than Docherty and Burgess have produced to 

 establish that pure carbon tetrachloride in doses of 5 to 8 cubic 

 centimeters will produce lesions in an adult liver save in very 

 exceptional circumstances or where a disorder of the liver already 

 exists. Another very important desideratum that we feel should 

 be borne in mind in connection with the work of both Smillie 

 and Pessoa, and Docherty and Burgess, is that neither publica- 

 tion contains definite information regarding the grade of purity 

 of the drug used. We are of the opinion that discussions regard- 

 ing the toxicology of carbon tetrachloride are futile unless they 

 are accompanied by a definite statement regarding the chemical 

 purity of the carbon tetrachloride that was employed in the 

 experiments. . 



In connection with the above, it should be noted that our 

 subject was necropsied three days after treatment, while 

 Docherty and Burgess's men went to autopsy six days, fourteen 

 days, and eighteen days, respectively, after the drug had been 

 administered. 



The foregoing clinical and pathological observations having 

 made it clear to us that our man had sustained the administra- 

 tion of 10 cubic centimeters of carbon tetrachloride without or- 

 ganic damage, and the other men having in the meantime shown 

 no ill effects, we decided to base our future work on the standard 

 afforded by him. The man was a fair physical representative 

 of the men with whom we were to deal. His weight before 

 execution was 54 kilograms, so that simple calculation showed 

 that he had been treated on the basis of 1 cubic centimeter 

 of the drug to each 5.4 kilograms of body weight. We there- 

 upon fixed as a maximum dose-basis for treatment 1 cubic centi- 

 meter of carbon tetrachloride to each 5.5 kilograms of body 

 weight. 



We consider it unnecessary at this time to review the work 

 of all those who have experimented in the treatment of hook- 

 worm infestation with carbon tetrachloride. Few apparently 

 have ventured to administer the drug in the doses we have 

 employed, yet some have reported toxic effects of a grave nature 



