CHEMISTRY OF DISEASE. 37 



the other uncut. The produce of the uncut ones was ob- 

 viously the better. The number of tubers is, no doubt, the 

 same, but the quantity is nearly double : the tubers of these 

 large and fine, of those small ; and probably they have not 

 increased in size since the haulm was cut, but they do not 

 appear shrivelled." 



(143.) If we examine the diseased potatoe, we find that 

 the structure of the plant is eventually destroyed ; the cells 

 which held the fluid and contained the starch granules no 

 longer exist ; and, in more advanced stages of the disease, 

 we observe that there is left either a mere shell containing 

 starch, or a shell containing a fluid holding starch and 

 broken-down cells in suspension. 



(144.) The disease manifests itself in a disorganization 

 of the framework of the plant. The cellular tissue, which 

 gives the form and consistence necessary for the organiza- 

 tion of the plant, is destroyed, the vital actions no longer 

 take place, and the plant dies. 



CHAPTER 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). 



(145.) THE diseased tuber possesses different qualities 



