PREFACE. 



have been inserted in connection with the chapters on 

 the abdominal and thoracic viscera. 



The dog has been selected in preference to the rab- 

 bit or the cat, the other animals usually employed for 

 such purposes, for several reasons. In most respects 

 its anatomy corresponds very closely to that of man ; 

 the size of the blood-vessels and other organs is rela- 

 tively large, and this is especially true of the thoracic 

 viscera and the neck region, which can be dissected 

 with more success by the beginner upon the dog than 

 upon the rabbit or the cat ; if small dogs are se- 

 lected, they will be found to be of a convenient size 

 for general laboratory use ; finally, most of the usual 

 physiological experiments and demonstrations are 

 made upon the dog, and a knowledge of its anatomy 

 will therefore prove particularly valuable to those who 

 intend to make a special study of physiology. 



The directions for dissection have been divided into 

 seven chapters, with the idea that a fresh dog would be 

 used for each chapter with the exception of those upon 

 the muscles of the shoulder and arm, the brain, and 

 the eye, requiring therefore four dogs for the entire 

 work, though a smaller number may be made to 

 answer. To obtain the most satisfactory results, how- 

 ever, one must be careful not to attempt to dissect too 

 much upon a single animal. When the student is at 

 work upon the blood-vessels he should not be required 

 to dissect at the same time the peripheral nervous 

 system. A much better knowledge of the circulatory 

 organs, especially of their relations to each other, will 

 be obtained if they are dissected as a whole. After 

 learning the anatomy of the blood-vessels the nerves 

 can be dissected with greater success, and their rela- 

 tions to the arteries and veins determined more easily. 



