COMPENDIUM 



OP 



HUMAN HISTOLOGY. 



INTRODUCTION. 



THE science of Histology has for its object the study 

 of the organic elements of the human body, in refer- 

 ence to their forms, the various changes which they 

 undergo, and the part which they perform in the con- 

 struction of its several tissues and organs. 



In the present state of the science all of the simple 

 elements of which the body is composed may be re- 

 duced to one of the following typical forms, viz : 

 1st, structureless material ; 2d, cells ; 3d, fibres ; 4th, 

 crystalline substance. 



Structureless material, or amorphous substance, 

 exists either as a liquid or solid ; in the former con- 

 dition it is of constant occurrence, in the latter it con- 

 stitutes the basis or fundamental substance of several 

 of the tissues, e.g. bone, cartilage, etc. 



The cell, in the largest acceptation of the term, is a 

 vesicle, varying greatly in shape, as well as in size, and 

 consisting essentially of an envelope, and contained 

 material of diverse appearance and nature. 



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