336 



THE POTATO AXB ITS COMMERCIAL PRODUCTS. 



Different varieties of potatoes yield, as the following table shows, very 

 different quantities of starch. 



Red potato --..- — 



Germinating potatoes - 



Kidney potatoes - - - 



Large red potatoes - - 



Sweet potatoes - - - 



Peruvian potatoes - - 



English potatoes - - - 



Parisian potatoes - - 



Starch. 



C3 

 w S 



fig 



Vegetable 

 Albumen. 



Gum, Sugar, 

 and Salts. 



15-0 



7-0 



1-4 



2-2 



15-2 



6-8 



1-3 



37 



91 



8-8 



0-8 



— 



12-9 



6-0 



0-7 



— 



15-1 



8-2 



0-8 



— 



15-0 



5-2 



1-9 



1-9 



12-9 



6-8 



1:1 



1-7 



13-3 



6-8 



0-9 



4-7 



Water. 



75-0 

 73-0 

 81-3 



78-0 

 74-3 

 76-0 

 77-5 

 731 



The following is an analysis of the potato, given by Mr Calvert :- 



Water 



Starch 



Epidermis, cellular tissue, pectose, pectine ; 



pectates of lime, soda, and potash 

 Albumen -------- 1-50 



Asparagin _-.__._ - 12 



Fatty matter 0-10 



Sugar, resin, essential oil T07 



Citrate of potash ; phosphates of potash, lime, 

 magnesia, silica, and alumina ; oxides of iron 

 and manganese - T56, 



74-00 

 20-00 



1-65 



4-35 



100-00 



Besides its ordinary use as human food, the potato is employed in rear- 

 ing live stock, and in distillation. Its fecula wanting gluten, does not 

 undergo the panary fermentation ; but it may be so mixed with wheat flour 

 a6 to produce good bread, and it is applicable to other purposes of domestic 

 economy, while the use of its starch is- extending in various forms. 



The results of examination on the comparative yield of starch in the 

 potato show that, while it abounds towards the latter part of the season, 

 it decreases when the tubers begin to germinate in the spring. It was found 

 by M. Pfaff that 2401b. of potatoes left in the ground contained of starch, 





lb. 





lb. 









.n August - - - 



23 



to 



25 



or 



96 



to 1 04 per cent 



„ September 



32 



j> 



38 



•>■> 



13-3 



„ 16-0 „ 



„ October - - - 



32 



j? 



40 



jy 



133 



„ 166 „ 



„ Nov. to March - 



38 



» 



45 



n 



16-0 



„ 18-7 „ 



„ April - - - 



38 



» 



28 



■>•> 



16-0 



„ H-6 „ 



„ May - - - - 



28 



}> 



20 



jj 



11-6 



„ 8-3 „ 



The quantity of starch remained the same during the dormant state of 

 winter, but decreased whenever the plant began to grow and to require a 

 supply of nourishment. 



