THE USES OF MORPHOLOGY. 245 



conformation of parts. Applied at times to the alterations 

 in the ' form ' of the several parts of the embryo, in contra- 

 distinction to ' histological,' which is applied to the transfor- 

 mation by which the tissues are gradually generated. In 

 comparative anatomy it is applied to the history of the modi- 

 fications of forms which the same organ undergoes in differ- 

 ent animals. 



MORPHOL'OGY is that branch of zoology, in its widest sense, 

 which treats of the general form (not outline) and organiza- 

 tion of animals, and the principles involved, as well as the 

 correspondence in the various forms of the several members 

 and parts, so far as they are comparable in any structural 

 characters, but entirely independent of the uses of the parts 

 and organs. It thus contrasts with animal physiology, which 

 treats of the organization in whole, so far as respects adapta- 

 tion to surroundings, as well as the various parts and organs, 

 so far as their uses and functions are concerned. To discover 

 the utility of organization in diverse animal forms and the 

 essential similarity in their mode of evolution, are the prin- 

 cipal problems within the province of morphology. GilL 



Mucous MEMBRANE (lining of alimentary, respiratory, and 

 genito-urinary tracts) consists of mucous membrane proper 

 and submucous tissues. The first consists of secretory tuber- 

 cles, follicles, and glands ; the second of elastic connective 

 tissue (capillary blood-vessels and nerve-filaments) by which 

 the secretory surface is nourished. Its free surface is lined 

 with epithelial cells, related to the mucous tissues beneath as 

 the epidermic cells are to the skin ; affords an extensive sur- 

 face for the great functional glandular processes of nutritive 

 absorption and the elimination of effete excretory products. 

 Its special function is to secrete mucus, and thus protect its 

 passages from the contact, attrition, and irritation of their 

 moving contents. Mucus consists of water, mucosine, and 

 salts. When rich in mucosine, it is viscid and tenacious ; 

 when salines predominate, it is scarcely more than transuded 

 blood-serum. E. D. Hudson, Jr. 



MUSK-DEER. A small deer of Central Asia ; a timid creature of 

 nocturnal habits, and is much hunted for its yield of musk, 

 which is obtained from a sac beneath the abdomen, on the 

 male alone. The flesh is esteemed, though that of the male 



