78 Animal Morphology. 



that modifications in colour are constantly occurring in 

 domesticated animals and farm stock, as well as in floral 

 culture, from some one or other of these causes modifying 

 the process of nutrition, and, therefore, of the condition of 

 ultimate molecules, however slight that change, chemically 

 considered, may be. 



But molecule may refer to two, three, or more atoms 

 constituting one primary compound or radical, which, as 

 an organic substance, enters into the composition of one, 

 two, or more animal or vegetable tissues or membranes ; 

 and each of such molecules, having its own special form, 

 will reflect rays in its own special and distinctive manner. 



Having sufficiently briefly referred to the subject of colour 

 in relation to vital manifestation, a few remarks will be next 

 given upon plasticity of cell architecture, arising from cell 

 differentiation and morphology passing from primary cells 

 on to membrane and tissue generally ; or the changes which 

 occur in the order of vital manifestation in animals. 



UPON ANIMAL MORPHOLOGY AND 

 DIFFERENTIATION. 



As in floral hues and tissues generally, between one structure 

 and another having separate colours, there is mostly some 

 change in the chemical composition of the respective tissues, 

 whose colours are distinct from one another ; as the floral 

 part is usually very distinct in its several parts from the 

 leaf, and the petals from the pistil, and pollen dust from 

 either ; so, in all organic architecture wherever new forms of 

 tissue or membrane require hardness, softness, elasticity, etc., 

 to enable them to fulfil the functions to which they are 

 destined, there we find, as the requirements may be, either 

 the cell walls, or coutense, accumulating special material 



