NUTRITION. 



1. Food substances of animals exemplified by the composition of milk: 



(a) Under the microscope milk seen to be an emulsion of fat in a solution of the 



remaining constituents. 



(b) By centrifuging the fat is separated as cream. 



(c) Acetic acid added to the remaining liquid precipitates the protein (casein). 



(d) The filtrate from (c) tested with Fehling's solution shows the presence of sugar 



(lactose). 



2. An organism having both plant and animal modes of nutrition : Euglena. 



