whole nourishment by the surface of their body, or by the 

 parietes of canals which traverse their interior. The sim- 

 plest gelatinous animalcules, which possess no internal 

 cavity, are also reduced to superficial absorption, and thus 

 form a transition to the mode of nourishment of the vege- 

 table kingdom. 



Besides describing the structure of all the inferior ani- 

 mals, and the changes which the organs and textures un- 

 dergo at different periods of life, this branch of Anatomy 

 examines the nature of the metamorphoses which various 

 classes of animals undergo before arriving at their perfect 

 state. And by comparing the adult organs of the inferior 

 classes, with the embryo state of the same organs in the 

 higher orders of animals, many extraordinary analogies 

 are discovered, which throw much light on the functions 

 of the parts, and serve to unravel the most complicated 

 and difficult forms of organization. By tracing back, for 

 example, the skeleton of fishes to that of quadrupeds and 

 man, the true nature and uses of all their complicated 

 arrangement of osseous parts have been discovered and 

 ascertained. And by comparing the human brain in the 

 earliest stages of its development, with the permanent 

 forms of that organ in quadrupeds, birds, reptiles, and 

 fishes, the most singular resemblances have been dis- 

 covered, which throw a new light on the gradual develop, 

 ment of that organ in the most perfect animals, and on its 

 remarkable structure in the inferior classes. 



By prosecuting these various enquiries* the views of the 

 Anatomist become enlarged, the speculations of the Physio- 

 logist are corrected or extended, and new principles are 

 discovered for the scientific arrangement of the Animal 

 Kingdom. 



Of all animals Man has the most elaborate and compli- 

 cated organization, and the structure of his body has been 

 a subject of constant observation and study, since the in- 

 fancy of the human race. Though debarred from human 

 dissection by superstition in the earliest times, the prac- 



