34 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



of the tubercle bacillus throws considerable light on the likelihood 

 of insect transmission. It has been found, for example, that the 

 longevitj' of the organism increases enormously as the environment 

 changes from light and dry to dark and moist. In other words, the 

 highest longevity occurs in exactly such places as are best adapted 

 for the breeding of the house fly. We consider that in all probability 

 one twentieth of the cases are contracted through the agency of insects. 

 We, therefore, have a probable annual loss in the United States of 

 $50,000,000 due to insects in connection with tuberculosis. 



In the case of typhoid fever, considering that one fifth of the loss 

 is due to insects, we have a total of $70,000,000 per year. 



In the group of enteritis and diarrhea no estimate of the total loss 

 seems to have been made. From the census report covering the years 

 1900 to 1904 we find that the number of deaths per 100,000 from these 

 diseases was 112.8. The death loss for the United States, on the basis 

 of life value of $1,700, would be $178,000,000 annually. To this we 

 judge there must be added at least an equal amount of loss oh account 

 of invalidism. We consider that one tenth of the loss may be due to 

 insects. This gives a total of $35,000,000 per annum chargeable to 

 insects in connection with these diseases. 



In the same way we conclude that the losses due to insects that are 

 concerned in the carriage of dysentery amount to $2,800,000 per year. 



In making the estimate of the cost of invalidism due to enteritis 

 and diarrhea and dysentery we believe that we are more than conserva- 

 tive. In the cases of the three important diseases; namely, malaria, 

 tuberculosis and typhoid fever, for which statistics are available, the 

 total loss is eight times the death loss, but in these instances we have 

 estimated the total loss as only double the death loss. 



We may summarize the losses due to the two classes of insects 

 which we have discussed, as follows: 



Malaria $100,000,000 



Splenetic fever 100,000,000 



Spotted fever 100,000 



Tuberculosis 50,000,000 



Typhoid fever 70,000,000 



Enteritis and diarrhea 35,000,000 



Dysentery 2,800,000 



Total $357,900,000 



We are certain that in making our estimates we have leaned far 

 towards the side of conservatism. For the moment we have not con- 

 sidered poliomyelitis, pellagra and several other maladies at all, and 

 other expenses chargeable to insects have been omitted. Take, for 



