163 



None of the feed extracts showed any acidity to methyl orange, a result quite to be 

 expected. Referring to methyl orange, Ostwald says "should the acid be weak, 

 only slightly ionisable (the ionization being still further reduced by the presence 

 .f i In- neutral salt formed in the liquid), the quantity of hydrogen ions on passing the 

 point !' neutralization is too small to allow of the formation of a visible amount of the 

 Donionised moleculefl of methyl orange, and the red color only appears after a con- 

 Mderahle excen has been added, and then only by degrees." 



The conditions thus described by Ostwald seem to be identical with what we have 



in these feed extracts. Five samples of Buffalo gluten feed required from 1.10 to 1.80 



<< of dccinormal alkali to neutralize the acidity of 1 gram of feed, using litmus; from 



usin- phenolphthalein, and from 2. 70 to 3.65cc, using Toepfer's reagent. 



Five samples <.f <ilo[,,. -luten feed, with the same amount of feed, required from 

 1 .:'" i" I .'' CC with litmus; 2.95 to 3.80 cc with phenolphthalein and from 2.90 to 

 3.80 cc with T<>epfer's reagent. 



(ream of corn gluten feed and Pekin gluten feed gave corresponding results with 

 the three indi< lule Douglas gluten feed showed the same relation, but a 



inurh lower aridit \ . (>.:!'> cc with litmus, 0.40 cc with phenolphthalein and 0.35 with 

 reairenl. 



The .-ample- ..f wheat bran, middling, and feed required 0.50 to 1 cc with litmus, 

 I .o with phenolphthalein and 1 to 1.80 with Toepfer's reagent. 



( otton-eed meal required 0.65 cc, 1 cc and 1 cc, respectively, with the three 

 imli< .1 



Th- .1 \erauc acidity f all the feeds was 1.18 cc with litmus, 2.37 cc with phenol- 

 phthalein and _'." cc with T'epfer's reagent. 



These retnultn c>rres|>ond perfectly with what we should expect if the acidity came 



from n of protein salts alone, or from salts of weak organic acids. I there- 



he a-sociation to take up the matter of acidity of cattle feeds and consider 



lio\\ the re.-ulis obtained by current methods can be applied to agricultural problems. 



The appended table pre-eni> the determinations in detail. 



Acidity of </ln ten feeds. 

 [In trrms of 1 gram of feed.] 



a Foundations of Analytical Chemistry, pp. 125, 126. 



