54 



Brockton, Mass. (on Oak Street), 

 Beverly, Mass. (on Hart Street), 

 Beverly, Mass. (beside railroad track), 

 Cohasset, Mass. (Barron's Island), 

 Hingham, Mass. (island in the millpond). 



Per Cent. 



^y2 



15 

 3 



18 

 5 



Taking the average of these results, we see that the total 

 number of apparently living eggs has been decreased by intro- 

 duction of the artificially developed Elacherie to about IJf per 

 cent. This result is shovpn graphically in Figs. 4 and 5, where 



Fig. 5. — Diagram showing average percentage of living eggs after introduction 

 of the disease. 



1 per cent, is equal to 1 square, the cross-lined spaces repre- 

 senting the percentage of dead eggs. 



Only those localities have here been tabulated on which we 

 had complete data from the beginning to the end of the experi- 

 ment. 



