Leeches 



47 



the temperature continuously moderately low. So far conditions 

 were favorable to the success of the experiment. On the other hand 

 the snowfall was remarkably heavy, so hea\"y, indeed, that it pre- 

 vented the taking of the supplementary steps recommended. In reply 

 to an inquiry Mr. Welch wrote me under date of March 8, 1920: 

 " Shortly after your visit here we had so much snow that we had to 

 abandon all work in the Park this winter ; the roads are all closed 

 and it has been and is still impossible to get around at all. There 

 are approximately seven feet of snow in the mountains now." It is 

 much to be regretted that conditions proved such as to leave the 

 results of the experiment in doubt. The following data were fur- 

 nished by Mr. Welch from his office records : The ice on the lake 

 attained a thickness of fourteen inches and the snow of twelve inches, 

 both remaining throughout the winter. The temperature frequently 

 reached -5° F. and remained continuously low until the latter part 

 of March. The normal water level in the lake was reached on March 

 twentieth. 



Owing to various circumstances I was unable to visit Carr Pond 

 again until August 2, 1920, during which week several days were 

 spent in attempts to determine whether the blood-sucking leeches had 

 been noticeably affected by the conditions existing at the pond during 

 the winter. Two lines of inquiry were carried out, as follows : 



First : all of the camp directors and others who were in a position 

 to know were requested to express an opinion concerning the relative 

 abundance and troublesomeness of the leeches during the simimer 

 of 1920 compared with that of 1919. Later, Mr. Brown made the 

 same inquiry independently in the form of a questionaire. The fol- 

 lowing table shows the results : 



NAME OF CAMP 



Leeches more 



or less numerous 



in 1920 than 



in igip 



Average 

 number of 



campers 

 bitten per 

 day in 1920 



Remarks 







About '2 



i"or'2 





Globe 





tJsed for bait. 



Jacob Riis and Tiinity 









'Much less 



Less 



More 



Not over i.. . . 



About 2 per 



week. 

 About 2 or 3 . . 



Not over i. 



1 or 2 



About 5 per 

 week. 



2 or 3 



Usually I or 2. 



ICamp in 1920. 

 IDuring 19 19 this camp 

 was always a prolific 

 source of supply. 





Hebrew Orphan Asylum, Boys 

 Branch. 



Nathan Hale 



the boys both summers. 

 Used for bait. Two or 

 three times as many and 

 larger than in 191 9. 



Martha Barbour 



Somewhat more . 

 About the same . 

 Much more 





Greenwich 



camp. 



Ramapo 



per day. 

 Six to twelve caught daily. 



Girls Patriotic League and Brook- 



lyn Girls. 







