trypsinogen: inactive precursor of trypsin; a substance secreted by the pancreas and converted to active trypsin by enterokinase in the small intestine
substance: the real physical matter of which a person or thing consists
artiodactyla: an order of hooved mammals of the subclass Eutheria (including pigs and peccaries and hippopotami and members of the suborder Ruminantia) having an even number of functional toes