THE BAT GUAXOS OF PORTO RICO AND THEIR FER- 
TILIZING VALUE. 
CONTENTS. 
Page. 
Introduction 3 
Description of guano deposits 4 
Chemical analyses of samples 9 
Vegetative tests with bat guanos 19 
Valuation of guanos 53 
General remarks on bat guanos 55 
Summary 61 
Appendix 64 
INTRODUCTION. 
Deposits of bat guano have been reported from the southern 
United States, most islands of the West Indies/ Brazil, Uruguay, 2 
the Philippines, Marianas, 3 the Federated Malay States, 4 India, 5 
Transvaal, 6 Egypt, Italy, Sardinia, southern France, the shores of 
the Mediterranean, and Austria-Hungary. 7 They evidently occur 
wherever conditions are adapted to the existence of bats in large 
numbers and suitable congregating places are afforded. 8 
As the composition of guanos depends more on the leaching, etc., 
to which they have been exposed than on the composition of the 
original substance, many of these deposits are similar to certain 
phosphatic guanos formed by sea birds. The individual deposits 
originating from sea birds, however, are much the larger, for although 
both birds and bats congregate in immense numbers, the birds con- 
sume much more food. 
Scattered through various publications many analyses of bat 
guanos can be found, although apparently no thorough study of the 
i Cousins, H. H., Local deposits of bat guano, Bui. Dept. Agr. [Jamaica], 1 (1903), No. 6-7, pp. 144-146. 
Ageton, C N., The origin, composition, and fertilizer value of the bat guanos of Cuba and the Isle of Pines, 
Modern Cuba, 3 (1915), No. 2, pp. 48-59. Miller, C. F., On the composition and value of bat guano, Jour. 
Indus, and Engin. Chem. , 6 (1914), No. 8, pp. 664, 665. 
2 Schroeder, J., Composition of bat guano from Uruguay. Rev. Assoc. Rural Uruguay, 44 (1915), No. 9, 
pp. 529-531. 
3 Kanamori, S., On bat guano from Marianne Islands. Bui. Col. Agr., Tokyo Imp. Univ., 7 (1907), No. 
3, pp. 461-464. 
« Dunstan, W. R., Report on four samples of bat guano from the Federated Malay States. Agr. Bui. 
Straits and Fed. Malay States, 4 (1905), No. 10, pp. 394-399. 
» Thompstone, E. , Bats' guano in Burma. Agr. Jour. India, 4 (1909), No. 4, pp. 379-381. 
single, H., The Wonderfontein caves. Transvaal Agr. Jour., 3 (1905), No. 10, pp. 217-221. 
7 Fritsch, J., The Manufacture of Chemical Manures, translated by D. Grant, London, 1911, p. 287. 
Riimpler, A., Die kauflichen Dungestoffe, revised and enlarged by R. Woy, Berlin, 1911, 5 ed., p. 127. 
8 Campbell, C. A. R., The eradication of mosquitoes by the cultivation of bats. Internat. Inst. Agr. 
[Rome], Mo. Bui. Agr. Intel, and Plant Diseases, 4 (1913), No. 8, pp. 1175-1181, pis. 2. In this article, the 
author gives interesting data on the amount of excrement voided per bat and results from an experimental 
bat roost which, he claims, show that it is commercially profitable to build roosts for the manure yielded. 
(3) 
