ISO THE ACTION OF THE LIVING CELL 



experiments of Sir Thomas Lewis (1924), who has 

 demonstrated that in young subjects wheals may be 

 formed on the skin by firmly stroking it with a blunt 

 instrument. The wheal formation is preceded by a 

 red tache which indicates a dilation of the capillaries 

 of the skin. These observations of Lewis of¥er irre- 

 futable evidence that some product liberated from the 

 injured tissues is responsible for the observed increase 

 in capillary permeability and the subsequent localized 

 edema. 



Lewis and Grant (1924) believe the substance 

 which is liberated from the tissues to be of a histamine- 

 like nature because they found that a similar wheal 

 formation follows the introduction of histamine into 

 the skin. It may be remembered that some investi- 

 gators have reached the conclusion that traumatic 

 shock is the result of the liberation of histamine by 

 the injured tissues; hence, on this basis, there exists 

 a distinct relationship between shock and vesication. 

 In this respect, then, these results are in agreement 

 with the author's cytost theor}^, the only essential dif- 

 ference being the names applied to the tissue break- 

 down product responsible for the observed physio- 

 logical changes. For the reasons given previously, the 

 writer prefers to adhere to the name cytost until the 

 exact chemical nature of the substance is known. 



To return to the problem of the immunity to mus- 

 tard found in the animals studied by the writer, it 

 seems obvious that the resistance developed is not 

 really an increased tolerance for this substance, but 

 is rather the expression of an increase in resistance of 

 the body cells to the substances liberated from the tis- 

 sues by the action of mustard. That is, during the 



