THE RELATION OF ZOOLOGY TO ALLIED S< I IV I.S 513 



some particular aspect of one or the other or both. Thus 

 Anatomy describes the structure merely, and, as the word is 

 generally used, it refers to the macroscopic structure, the general 

 arrangement of parts which can be made out with the naked 

 eve, and hence is sometimes called gross anatomy. Histology, 

 or Microscopic Anatomy, on the other hand, describes the minute 

 structure for the study of which the microscope is necessarv. 

 Taxonomy, or Classification, attempts to arrange plants and 

 animals in natural groups, so as to show as far as possible their 

 relationship to other plants and animals ; this science is often 

 called Systematic Botany in the classification of plants, and 

 Systematic Zoology in the classification of animals. The 

 science of the Distribution of organisms includes their horizontal 

 or geographical distribution, their vertical or bathymetrical dis- 

 tribution, and their geological distribution, or distribution in 

 time. This latter division of the science deals with animals and 

 plants which have lived in more or less remote periods of the 

 earth's history, and are known to us by their fossil remains ; 

 their study constitutes the special science of Palaeontology, the 

 science of fossil organisms. Occasionally plants and animals 

 develop abnormally ; the supernumerary legs and horns which 

 are sometimes found in the higher animals are familiar examples 

 of this phenomenon; such individuals are known technically as 

 monsters, and the science which makes a study of them is 

 called Teratology. The science of the development of the 

 individual is known as Embryology, or sometimes as Ontogeny , 

 it treats of the changes which an organism undergoes from the 

 time when it is in its simplest, most primitive condition up to its 

 adult form ; this science is necessarily both morphological and 

 physiological. The science of Phylogeny or the development 

 of the different types or races of animals or plants is largely a 

 theoretical science, which by using the facts of Anatomy, 

 Embryology, and Palaeontology attempts to trace the evolution 

 of one group of organisms from another. The science of 

 Physiology deals with all the activities or functions of an organ- 

 ism, whether in health or disease, but the phenomena of the 

 latter condition are generally considered under the special 

 science of Pathology, a science which is both anatomical and 

 physiological ; thus far it has concerned itself chiefly with man, 



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