CONTENTS. XI 



CHAPTER V. 



;W,V, CHEMISTRY OF DISEASE. 



Diseased tuber different in quality (145). Mode of analysis (147). 

 Value of analyses (148). Analyses (149) Deficiency of fibre 

 (150). Starch in excess (151). Albumen destroyed (152). 

 Solly's analysis (153). Diseased potatoes partially destroyed 

 (154). Sugar in diseased potatoes (157). Butyric acid (158); 

 liable to fermentation (159, 160). Difference between the sound 

 and diseased potatoes (161). PAGE 37. 



CHAPTER VI. 

 RELATION OF THE DISEASE TO INTERNAL CAUSES. 



Gangrene from old age (164). Kinds not equally affected (165). 

 Progress of disease in Chelsea wild plant (166) ; in Uhde's plant 

 (167) ; in various varieties (168) ; in plants requiring much leaf 

 (170). Horticultural Society's plant (172). Greatrex's account 

 (175). Storr's account (176). Latham's account (177). Early 

 varieties less liable to disease (179). PAGE 42. 



CHAPTER VII. 



RELATION OF THE DISEASE TO EXTERNAL CAUSES, TEMPERA- 

 TURE, LIGHT, ELECTRICITY, ETC. 



Gangrene not the result of any internal cause (180). Effect of tem- 

 perature upon plants generally (181). Potatoe thrives in various 

 climates (182). Cold (184). Influence of temperature (185) ; 

 upon the decay of tubers (187). Effect of light upon plants 

 (190). Effects of light upon tubers (193). Influence of electri- 

 city (194). Influence of atmospheric moisture on plants (195). 

 Excessive moisture a cause of disease (196) ; its influence on the 

 disease (197); effect on the tubers (199); other atmospheric 

 agents (200). Effect of winds (201). PAGE 47. 



