MAINTUAL OF CATTLE-FEEDIJS^G. 



27 



tlie albuminoids of the animal body, and liave, like tliem, 

 been called albuminoids or protein bodies. 



The name 2)rotein was Ubed by Mnlder to debignate a 

 supposed substance which formed the basis of all the 

 albuminoids. The word is no longer used in this sense, but 

 is very commonly met with as a collective term for all the 

 albiuninoids, and we shall thus use it in the present work. 



The vegetable albuminoids which have as yet been in- 

 vestigated may be divided into three groups, album ui^ 

 case in J saidjlhn7i, havhig more or less resemblance to the 

 corresponding groups of anin^al albuminoids, though it is 

 doubtful if the two are identical. 



Vegetable Albumin appears to oecm^ chiefly in the 

 young and growing parts of plants, w4iile in the older 

 parts it is converted into other forms of protein. It is 

 contained, dissolved in small quantities, in the sap of fresh 

 plants, and coagulates when the sap is heated. 



Vegetable albumin is soluble ia cold water, in dilute potasb solu- 

 tion, and in dilute acetic acid ; it is insoluble in alcohol, and is very 

 similar in all ifcs properties to animal albumm. Its composition varies 

 somewhat according to the source from which ib is derived. The fol- 

 lowing table shows the extremes of variation : 



Carbon . . . 

 Hydrogen 

 Nitrogen . 

 Oxygen . . 

 Sulphur . 



Animal albimim (av.). 

 Por cent 



53.5 

 7.0 



15 5 



22 4 



16 



Vegetable albumin. 

 Per cent. 



7.1- 7.7 

 15.5-17.6 

 20.6-23.0 



0.8- 1 6 



The composition of animal albumin is not far from the average for 

 vegetable albumin, but the identity of the two is, at best, doubtful. 



