58 INTRODUCTORY. 



§ 129. Reasons for Giving Unusual Prominence to the Vis- 

 cera.— It is stated by Macalister (British Association Eeport, 1877, 

 p. 94), that "at least 600 bodies are annually examined in the dis- 

 secting rooms of G-reat Britain and Ireland;" yet how few are 

 the published observations respecting the characters, constant or 

 variable, of any parts other than the bones and the muscles. In 

 this country the case is still worse, and we have no journal espe- 

 cially devoted to Anatomy and Physiology. 



This comparative neglect of the internal organs is probably due, in great part, to the 

 fact that, as remarked by the senior author, {2, 9), the average " human subject is rarely 

 available for the study of viscera. Usually some of them are diseased. The heart is apt 

 to be full of injection-mass. The brain and abdominal viscera decay so rapidly that some 

 of their important features are soon obliterated ; and when, as is customary, their removal 

 ia postponed until after the examination of the overlying muscles, their condition is often 

 such as to render them unfit for preservation. How many students have gained a good 

 view of the thoracic duct, or the sympathetic ganglia ? How often has it been ascertained 

 vrhether a subject has two pancreatic ducts or only one? Is a satisfactory examination 

 ■of the brain made by the majority of dissectors?" In short, do not the larger number of 

 medical students regard the viscera, even the heart, as simply a mass of ill smelling 

 material, diflBcult to examine, not very instructive, and worthy only of the waste pail ? 



Whatever be the cause of this inattention to the viscera, the fact leads us to give 

 ample space and illustration to these organs as they exist in an animal peculiarly adapted 

 for their study and preservation. Moreover, although a predilection for surgery prevails 

 among medical students, most of the diseases they will have to treat affect the viscera 

 rather than the skeleton and its muscles; physiology, too, is largely splanchnological, and 

 a correct knowledge of the brain is yearly more desirable in connection with the pro 

 gress of rational Psychology. 



Lastly, notwithstanding the general preference of systematic zoologists for skeletal 

 characters — a preference certainly based upon convenience, and, in respect to fossil forms, 

 u.pon absolute necessity — we are disposed to think, as suggested by GiU {1, p. xxvii) 

 and the senior author {22, 189), that the more comprehensive vertebrate divisions should 

 be founded upon cerebral and cardiac characters. 



