POETO RICO. 229 



dentally also determinations of the energy values of the mixed hay 

 used as the basis of the rations were made. Two animals were used 

 for the investigation, which included 5 periods of 3 weeks each 

 for each animal, or 10 in all, during each of which the metabolism 

 of the animals was investigated by means of the respiration calorim- 

 eter, the methods of experimentation being substantially the same 

 as in previously published work with a few minor changes. 



During the year Bulletin 128 of the Bureau of Animal Industry, 

 giving a full discussion of the experiments on the influence of type 

 and age on the utilization of energy by cattle, outlined in last year's 

 report, was completed and the results of investigations by J. A. Fries 

 upon the methods of bomb calorimetry were published as Bulletin 

 124 of the same bureau. 



PORTO RICO. 



Pol-to Rico Agricultural Experiment Station, Mayaguez. 



Under the supervision of A. C. True, Director, Office of Experiment Stations, 

 United States Department of Agriculture. 



D. W. May, M. Agr., Special Agent in Charge. 



The new office and laboratory building, which was begun in 1909, 

 was completed and the equipment installed during the past year. 

 This building has proved well adapted to the comfort and con- 

 venience of the staff. 



The work of the station has been along the same lines as pre- 

 viously reported. In the chemical department a considerable amount 

 of analytical work has been carried on, and in addition investigations 

 have been made on soils and plant nutrition. One of the problems 

 taken up was the formation of calcareous hardpan, which was found 

 to be present in a number of localities, causing considerable loss in 

 connection with various plantings. A large amount of work has 

 been carried out on the causes and means for correction of chlorosis 

 of pineapples in certain districts of the island. This trouble seems 

 to be connected with the lime content of the soil, and in connection 

 with this investigation a study has been begim on the lime require- 

 ments of various plants. The work on the sick soils due to the super- 

 abundance of bacteria has been continued, and field experiments on 

 disinfection are in progress. 



The entomologist has continued his studies on insect pests of citrus 

 trees, and prepared a bulletin describing the principal insects and 

 suggesting means for their control. An investigation has been begun 

 on the insects attacking coffee, particular attention being paid to 

 the injury caused by ants. Through the station considerable interest 

 has been aroused in beekeei)ing, and a large number of broods have 

 been disposed of to go to coffee plantations. 



