470 SCIENCE PROGRESS. 



9. The question of manurino- is a difficult one. Many 

 have put clown the increase of disease in the cane-fields to 

 this cause. A lack of adjustment between stimulatini>' and 

 feeding manures will certainly lead to crops of small re- 

 sisting powers ; and little trouble has been taken in the 

 past to determine the needs of the plant in different soils. 

 Scientific manuring will vary with almost every field, 

 depending not only on the chemical composition of the soil, 

 but also on its physical condition. In the great majority of 

 cases, general cane manures have been used without special 

 study of the soil, resulting in waste and, possibly, injury to 

 the plants. But while artificial manuring has probably been 

 harmful in certain cases, the principle is sound enough ; 

 and those have far more reason on their side who trace the 

 prevalence of disease to the exhausted condition of the soil 

 on the worn-out estates where manurino: has been neolected. 

 The careful comparison of the effect of different combina- 

 tions of manures upon certain selected canes has been a 

 subject of special study in the v^arious sugar experimenial 

 stations} A mass of facts has thus been accumulated 

 which should place every planter in a position to test the 

 requirements of his own fields. No praise is too high 

 for the patient manner in which the various Government 

 analysts have pursued these studies, frequently amid the 

 ill-concealed hostility of the planting body. 



It is well known that excessive nitrogenous manuring 

 renders corn more liable to mst ;' and a similar observation 

 has been made regarding the sugar-cane. In some carefully 

 conducted experiments on a Demerara sugar- estate to de- 

 termine whether any relation existed between disease and 

 manure, Harrison has demonstrated that the amount of 

 disease was largely proportional to the nitrogen in the 

 manure.^ 



10. A good deal of study has been devoted to de- 

 termining the chemical constitution of the cane at different 

 periods of its growth,* as well as the comparative compo- 

 sition of healthy and diseased canes, without, however, 

 having at present yielded much result of economic import- 



1 Reports. - Berlese. ^ Harrison (2). •* Went (2) ; Sagot et Raoul. 



