SCOTCH HILL SHEEP. 



275 



therefore of considerable importance to estimate the amount of 

 true albuminoids apart from the other nitrogenous matters. 

 In most of the published analyses of fodders, except the most 

 recent, the " albuminoids " have been estimated by multiplying 

 the total nitrogen found by 6*25 or by 6'33. Many methods 

 have been suggested for the separation of the albuminoids in 

 foods from the other nitrogenous substances, with a view to their 

 subsequent determination. Xearly all these consist in extract- 

 ing the food with water or acidulated water, to which is added 

 some substance known to coagulate and render insoluble 

 albuminoids, whilst it is assumed that the whole of the amides 

 and other nitrogenous matters pass into the filtrate ; a nitrogen 

 determination is then made in the insoluble portion. Church 

 {Lahoratory Guide, 5th edit., p. 229) proposes a 4 per cent, 

 solution of carbolic acid with a little metaphosphoric acid ; 

 Eitthausen used copper sulphate and copper hydrate ; Sestini 

 {Landvnrth. Versuchs-Stationen, xxiii. 305), lead acetate ; Hoppe- 

 Seyler and Schulze, ferric acetate ; Hofmeister, lead hydrate ; 

 tannin has also been used ; Stiitzer {Journal fiXr LandwirtJischaft., 

 1880) proceeds by treatment with water containing a little 

 lactic acid and precipitation of the dissolved albuminoids with 

 copper hydrate. In some cases mere boiling with water appears 

 to be sufficient to coagulate all the albuminoids, and this was 

 found to be the case in some samples of hay examined by 

 Armsby {Rept. Conn. Expt, Station, 1879). 



In the fodders now examined the albuminoids were detsr- 

 mined by Church's carbolic method and by the copper hydrate 

 process (see Church's Lahoratoryjukiide, p. 229). In all cases the 

 results by the last process were slightly higher than those by 

 the former ; this may be due to the presence of a small amount 

 of nitrogenous acid forming an insoluble compound with the 

 copper hydrate. 



The results of the analyses were as follows : — 



* Containing albuminoids by carl.)olic method, 



by copper hydrate, 



>» 





