63 
Only 91 of the 247 samples analyzed contained 1 per cent or more 
of total nitrogen. In 22 of the 91 samples 50 per cent or more of the 
total nitrogen was present as ammonia and nitrate. Vegetation 
experiments with 35 samples were quite uniform in showing that the 
nitrogen present in any form other than ammonia or nitrate had 
practically no immediate availability. 
A conservative value assigned the different guanos, on the basis of 
prices of fertilizing elements prevailing before the summer of 1914, 
varies between and $47.60 per dry ton, the average value of the 
247 samples being $7.14. 
General conclusions are drawn concerning bat guanos as fertilizers, 
utilization of Porto Rican deposits, materials with which guanos 
should be compounded, mode of application, and crops and soils on 
which they should be used. 
