98 PUBLIC HEALTH CHEMISTRY 



Cl, etc.) ; addition of " improvers " (acid-phosphates of K, 

 Mg and Ca; H 3 PO 4 ; diastase, etc.). 



Animal and Vegetable Parasites. The corn weevil 

 (Calandra granaria), the ear cockle (Vibrio tritici), ergot 

 (Claviceps pur pur ea], smut (Uredo segetum), bunt (Uredo 

 fcetida or Tilletia caries), rust (Puccinia graminis), Mucor, 

 Aspergillus and Penicillium ; Acarus farina. 



Wheat Flour. Examine microscopically, physically, 

 and practically (by making bread). Should be white in 

 colour, silky to touch, free from smell or odour, and not 

 yellow or gritty. Moisture : dry 5 grm. in water-oven 

 (should not exceed 18 per cent). Ash : ignite (not more 

 than i per cent). Total proteid, from Kjeldahl N x 6-25 

 (not less than 8 per cent). Cold-water extract, (10 per cent) 

 (should not exceed 4-7 per cent). Acidity, none. 



Glutin. The proteins consist chiefly of a globulin and 

 an albumose which, when acted on by water, unite to form 

 glutin (from gliadin and glutinin). Estimate thus : weigh 

 10 grm. of flour and put into a porcelain dish. Add pure 

 water from a burette, stirring the while with a glass rod 

 so as to make a well-mixed dough. Be careful to add the 

 water slowly, using about 4 c.c. When made, let the 

 dough stand for fifteen minutes, then pour a little water 

 on and stir about with the rod to let the water wash out 

 the starch. Repeat until washings are free from starch, 

 as tested by iodine. (After a time the glutin becomes so 

 coherent that it can be worked with the fingers.) Dry, and 

 weigh. If time does not permit of drying, weigh moist 

 glutin and divide weight by 2-9. Dry glutin ranges from 

 8 per cent to 12 per cent (reject if below 8 per cent). 



Cold Water Extract. Weigh 20 grm. into a dry flask, 

 add 200 c.c. aq. dest., and shake for five minutes. Allow 

 to stand twenty-five minutes. Decant off clear liquid and 

 filter through a dry paper. Evaporate 50 c.c. in water- 

 oven to constant weight, and this gives total soluble 

 extract, consisting of sugar, gum, dextrin, soluble albumin, 

 and phosphate of potash. Ignite, and weigh ash, which 

 is phosphate of potash. The acidity (if any) can be 

 determined by using 100 c.c. of the cold-water extract. 



Mineral Matter. Shake 100 grm. of the flour with 

 200 c.c. of chloroform in a separator. Allow to stand, when 



