146 ANATOMY AND PHYSIOLOGY 



gorge when handled. It is ejected by an antip 

 staltic movement of the viscus. When the crop : 

 succeeded hy a gizzard, the food is soon urged, in 

 small quantities at a time, into its opening, where 

 is subjected to the action of the teeth or horn 

 ridges which cover its interior. The effect of thu 

 grinding process is so decisive, that it is in a sho 

 time reduced to a homogeneous pulp, which is calle 

 chyme. When the gizzard is wanting chymifactio 

 takes place in the crop. But the chyme does no 

 attain the highest degree of elaboration, till it ha 

 been for a time in the chylific ventricle. Here 

 generally assumes a deeper colour, and the chyle 

 separated from it. The latter is a thick liquid of 

 whitish, brown, or greenish colour, and is found un 

 der a microscope to consist of minute globules, 

 production is the grand object to which all the pre 

 vious processes tend, for it is the substance whic 

 forms the basis of all the nutritive fluids. A 

 intermixture of bile has always been regarded 

 essential to its nature, and in the case of insec 

 this ingredient has long been supposed to be supplie 

 by what were formerly described as the bile- vessel 

 But several eminent physiologists have lately enter 

 tained some doubts on this subject, from observin 

 that the so called biliary vessels empty themselves i 

 a part of the canal behind the place where the chy 

 began to be absorbed; that their contents, whe 

 analysed, have little resemblance to gall, but consis 

 in a great measure of uric acid ; and that many in- 

 sects have other secreting organs which empty them- 



