INDEX. 157 



it exists in the plant, 19; composition of, ib. ; quantity variable, 

 ib. ; potatoe, manufacture of, 24 ; uses of, 25 ; St. Etienne's ma- 

 chine, 24 ; conversion of, into dextrine, 25 ; manufacture of 

 sugar from, substituted for arrow-root, 24 ; in diseased potatoes : 

 sometimes superabundant, 39 ; generally deficient, ib. ; may be 

 extracted for useful purposes, 41, 137, 138. 



Stramonium attacked by the Aphis vastator, 85. 



Storr's account of the potatoe disease, 46. 



Sugar made from potatoe starch, 25 ; found in diseased potatoes, 

 41 ; cane affected by an Aphis, 92. 



Sweet potatoe. See Convolvulus battata. 



Sycamore attacked by an Aphis, 92. 



Syrphidae destroy Aphides, 104. 



Temperature, effects of, on the potatoe plant, 48 ; on the decay of 

 tubers, 48, 49. 



Tobacco not attacked by the Aphis vastator, 85. 



Tomato attacked by the Aphis vastator, 86. 



Tuber. See Potatoe. 



Turnip attacked by the Aphis vastator, 74 ; mode and progress of 

 the attack, 74, 79 ; mode and progress of attack similar to that 

 in the potatoe, 79 ; fingers and toes, explanation of, 75 ; speedily 

 becomes putrid, 76 ; bad odor exhaled by, ib. ; attacked by fungi, 

 ib. ; attacked also by the Aphis brassicae, 77 ; preferred to the 

 potatoe by the Aphis vastator, 78 ; Swede attacked by the Aphis 

 vastator, ib. ; to a less extent, ib. ; crops destroyed by the flea in 

 1786, 98. 



Ure, Dr., analysis of the potatoe plant from, 17. 



Wasps at Selborne in 1783, 100. 



Wheat plants attacked by the Aphis vastator, 86, 87 ; by another 

 Aphis, 87. 



White, Rev. G., instances of excessive numbers of insects, 99. 



Wild potatoes introduced in modern times, 11, 14 ; peculiarities of, 

 ib. ; not in use now, 17 ; plants resist the disease, 42, 43 ; resist 

 the Aphis vastator, 85. 



Wine made from potatoes, 26. 



