13 



that had fermented in a stack, and when subjected to chemical 

 analysis it showed precisely the same changes as were found to 

 have taken place in hay which had heated naturally. The tem- 

 perature of the receptacle in which the artificially heated hay was 

 kept was never less than 203 degrees F., so that the conditions 

 were such as to preclude the activity of living organisms. In 

 order, however, to verify the result, hay was sterilised at a tem- 

 perature of 248 degrees F., and this material also, when put 

 through laboratory treatment, attained the same condition and 

 composition as heated hay from a stack. 



The investigators are therefore perfectly confident that they 

 have proved satisfactorily that the fermentation of a hay stack is 

 in no way associated with the activity of living organisms, though 

 they do not yet feel justified in attempting to offer an explanation 

 of the causes that induce the high temperatures which are met 

 with in the interior of a mass of fermenting hay. As they con- 

 sider that they have shown that this form of so-called fermentation 

 is purely chemical, they are disposed to cast doubts on the neces- 

 sity of any bacterial action in the case of many other similar 

 processes, as, for example, in the maturing or fermentation of 

 tobacco.* 



THE CULTURE OF THE CENTRAL AMERICAN 



RUBBER TREE, Vl.f 



{Continued from Bulletin for December, 1904-) 



By O. F. Cook, Botanist in charge of Investigations in Tropical 

 Agriculture, U. S. Department of Agriculture. 



THE CULTURE OF CASTILLOA. 

 In attempting to plan a rational culture for Castilloa it will be 

 worse than useless to insist upon all or any of the cultural 

 measures which have been found desirable with coffee, cacao, or 

 other tropical crops. Castilloa is not cultivated for the leaves like 

 coca, for the flowers like cloves, for the fruits like oranges, nor 

 for the seeds like coffee. The increase of the size of the trunk and 

 of the amount of milk contained in its inner bark are objects of 

 cultural solicitude. 



SHADE IN THE CULTURE OF CASTILLOA. 



SHADE NOT A NECESSITY. 



Much of the preceding discussions of the habits of Castilloa 

 and of the climatic conditions suitable to its culture may also serve 

 as preliminary to the consideration of the question whether planta- 



* Dr. Loew, under the direction of Piof. H- T.Galloway, chief of the Division of Vege- 

 table I'hysioiogy & Patholo-y, U. States DepHrtraeut of AKricultur^ has investigated 

 the curing and fermentation of cigar leaf tobacco. The result of his work is to show 

 that the princijial changes that take place are due to the action of soluble f.rraents or 

 enzymes, not bacteria; and that the development of colour and aroma isdue principally 

 to the action of oxidizing enzymes. (J/wc. Publications, No- 52, 1899.) [Editor.] 



t Extract from U.S. Uepartmeat of .\griculture. Bull. No. 49, Bureau of Plant 

 Industry. 



