History and Progress of Cmnparative Anatomy. 363 



We are indebted to this anatomist for several valuable facts 

 in animal anatomy and physiology. He was among the first 

 who shewed the development of the chick in oro, and distin- 

 guished the different parts of the foetus as they come into view. 

 He has traced also, with great accuracy, the growth of bone, the 

 junction of the epiphyses, and the different stages of the pro- 

 cess of ossification. He recognised the canal of the spinal chord, 

 and shewed that the matter of which it consists, though white 

 at the sides, is gray or cineritious in the centre, as well as its 

 fibrous structure. He distinguished the nerves of the spinal 

 chord into anterior and posterior rows. He discovered two 

 muscles of the nose. He described the quadruple stomach 

 of the ruminating animals, and the lungs of the oviparous qua- 

 drupeds, as the turtle, tortoise, and crocodile, were then named. 

 He gives minute accounts of the anatomical structure of the 

 tortoise, hedgehog, and bat ; dissections of several birds, with 

 an account of their tympanal cavity, and retnarks that they have 

 only one tympanal bone. He describes the tongue of the wood- 

 pecker, its stomach, crop, &c. ; and, in investigating the anato- 

 my of the serpent tribe, he is the first who describes the poison- 

 vesicles or glands, — a discovery, the merit of which has been 

 unjustly ascribed to Rhedi. 



He had made numerous experiments on living animals to de- 

 termine the motion of the heart; and he found himself justified 

 in concluding that dilatation of the ventricles succeeds contrac- 

 tion of the auricles, and the converse ; that the apex approaches 

 the base during systole, and is removed during the diastole ; 

 and consequently that the heart is shortened during contraction. 

 Two facts also, not unworthy of the attention of modern phy- 

 siologists, he recognised in these experiments. The first, the 

 well known fact, that the right ventricle continues to contract 

 long after the death of the left ; and the second, that the base of 

 the organ continues to move long after all motion has ceased in 

 the apex. By exposing the brain in animals, as he occasionally 

 saw done by accidental injury in man, he recognised, with Co- 

 lumbus, the fact, that the pulsatory motion of that organ de- 

 pends on the action of its arteries. He had also remarked in 

 injuries of the head in the human body, that portions of brain 

 might be removed without serious injury to the functions. In 



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