PREBPACE: 
For the introductory study of the structure and physiology of a 
typical vertebrate, there is no form better adapted than the 
common frog. The present course is based largely on the well- 
known works of Huxley, Marshall and Holmes; the author’s task 
has been mainly that of simplification and adaptation, primarily 
to meet the needs of his own students. These directions are the 
outcome of eight years’ experience in teaching the biology of the 
frog in the University of Michigan, Syracuse University, the 
University of Wisconsin and the Michigan State Normal College ; 
the author is naturally much indebted to his former teachers and 
associates, particularly to Prof. S. J. Holmes. 
As a general rule, the order of topics in the text should be 
followed, since it is planned to give a distinct picture of each 
organ system in its relation to the whole, with the greatest 
economy of time and material. For pedagogical reasons an ex- 
ception should be made in the case of certain histological topics: 
it seems best to begin the microscopical work with the study of 
some simple tissues, such as the stratum corneum, cartilage, and 
perhaps also blood, connective tissue and unstriated muscle fiber, 
before attempting the study of cross-sections of such complex 
structures as the alimentary canal and the kidney. By following 
the sequence of topics in this manual, all the study of gross 
anatomy, excepting the work on the circulatory system and the 
skeleton, may be done with a single specimen. 
In connection with the laboratory work the student should read 
the corresponding portions of Holmes’ Biology of the Frog. As 
a rule the reading on a given topic should follow, rather than 
precede, the laboratory study of that topic. 
In case time is limited, the work may be shortened by a judici- 
ous omission of topics. The chapters on the eye and the ear, the 
thyroid glands, and even the skeleton and the muscles, may be 
omitted without serious detriment to the remainder of the work. 
In case material is limited, an entire frog may be saved for each 
student by omitting the special dissection of the venous system. 
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