136 THE SCIENTIFIC FEEDING OF ANIMALS 



2 to 3 hours, and then kept in a refrigerator for several hours. If hemolysis takes 

 place, recognizable by clarification and red coloration of the fluid, saponin is present. 

 For the examination of bread, take 10 grams of finely grated and subsequently 

 sifted bread crumbs, put in an Erienmeyer flask with 5 c.c. of 90 percent alcohol and 

 5 c.c. chloroform. Bring to boiling point; filter at once through dry filter. The 

 residue is treated in the same manner with alcohol and chloroform for a second 

 and a third time. The three filtrates are mixed and evaporated on a water bath. 

 The residue is dissolved in 5 c.c. of physiological salt solution, filtered and, if nec- 

 essary, neutralized. Take 2 or 3 c.c. of the clear filtrate and add a few drops of a 

 suspension of red blood corpuscles and proceed as above. 



3. Microscopic Examination 



For microscopic examination 30 to 50 grams of a good average sample of feed- 

 ing stuff are necessary. 



Preparation of the Feeding Sttiff for Microscopical Examination 



Preliminary tests are made with the naked eye. The material, if light colored, 



Fig. 55. Sedimentation 



is spread out on a smooth sheet of black paper; if dark colored, on a smooth sheet 

 of white paper. It is then searched for clumps or particles of unusual size or ap- 

 pearance that would indicate spoiled or impure material. These are preserved for 

 the time being for later examination for the presence of mites, mold fungi, etc. 



Oil cake should be ground into a fine meal. 



Meals and brans are separated into four grades by means of Nobbe's compound 

 sieve, which consists of three different sieves with 1J4, 1 and ^ mm. meshes. 



The upper sieve retains the coarse admixtures, pieces of the rachis of the heads 

 of grains, skins and glumes (chaff), pieces of straw, large seeds of weeds, vetches, 

 corn cockle, dodder seed and ergot. 



The second sieve retains the smaller sized weed seeds, Atriplex (notchweed), 

 Capsella (shepherd's purse), Chenopodium (goosefoot). Euphorbia (spurge), Lep- 

 idium (cress), Papaver (poppy), Urticaria (nettle), Galium (cleavers), Viola (vio- 

 lets) and broken seeds, millet, rice and pea hulls, ground or broken pits of stone 

 fruits, oat hulls, pieces of caterpillars, moths, mouse excrement, etc., as the case 

 may be. (Test with magnifying glass.) 



In the third sieve the shells or skins of weed seeds and mites are commonly found. 

 Contents of this sieve should be examined with aid of a magnifying glass. 



The contents of the fourth compartment are used for microscopical examination 

 of the character of the starch grains, the presence of microorganisms (smut and 

 mold fungi) and, aided with iodin solution, the presence of mineral matter (sand, 

 chalk, gypsum, kaolin). The presence of mineral substances is frequently sug- 

 gested by the dust which they make. They are not stained, either blue or brown, 

 by iodin. 



