1820.] Fhysical Science during the Year 1819. 113 



ascribes respiration, or the faculty of breathing ; the capacity 

 of the chest being by their means successively enlarged and 

 diminished, and thus air alternately expelled and inhaled. He 

 thinks also with great probability that the movements of the 

 heart and the circulation of the blood are powerfully influenced 

 by the same resiliency. (Phil. Trans. 1820, p. 29.) 



The following works have been lately published on this sub- 

 ject, to which, from their nature, we must content ourselves with 

 referring our readers : 



An Experimental Licjuiry into the Nature, Causes, and Varia- 

 tions, of the arterial Pulse. By Caleb Hillier Parry, M.D. F.R.S. 



Additional Experiments on the Arteries of warm blooded 

 Animals, &,x. By Charles Henry Pariy, M.D. F.R.S. 



An Essay on the Forces which circulate the Blood, being an 

 Examination of the Difference of the Motions of Fluids in living 

 and dead Vessels. By Charles Bell, F.R.S. E. Surgeon to the 

 Middlesex Hospital, &c. 



II. Secretion and Secreted Products. — As every part of animal 

 bodies is formed from the blood, they may be all considered as 

 secreted products, though the term is usually limited to those 

 substances formed from the blood by a peculiar glandular appa- 

 ratus. We shall, however, for the sake of convenience, take the 

 word in its general signification. 



The Teeth. — We have been informed that an eminent French 

 physiologist, M. Blainville, has lately advanced the opinion that 

 the teeth are to be considered as hairs. A similar opinion was ad- 

 vanced in 1 8 1 1 by Dr. Prout, who at that time drew up the sketch of 

 a paper, the object of which was to prove that the teeth are to be 

 considered as appendages to the integuments, and to be classed 

 with horns, nails, &c. This opinion was principally founded 

 upon extensive anatomical inquiries, showing the analogy between 

 the formation of the teeth, and horns, feathers, &c. and partly 

 also upon physiological and pathological reasonings. The paper 

 was never published, owing to reasons which need not be men- 

 tioned, but the opinion was stated to many of the author's friends 

 at the time ; and he intends at some future opportunity to lay 

 the subject before the public in an extended form. 



IIl.NervousSi/stem,anditsFunctions. — It would be well for phy- 

 siology if its cultivators would leave for a while this abstruse and 

 difficult subject, and turn their attention to something more 

 within their power ; that is to say, if they would make them- 

 selves better acquainted with the ultimate chemical and mecha- 

 nical constitution of organic bodies ; for till this is known, it is 

 evident we can hope for very little real p^rogress in physiology. 

 We may here allude to the controversy that has been lately car- 

 ried on in the medical journals between Dr. Wilson Philip and 

 some other gentlemen on nervous action, &c. but we do not 

 think it necessary to enter upon the subject. Those who are 

 interested in the dispute may consult the original work of Dr. 

 Philip, entitled " An Inquiry into the Laws of Vital Functions," 



Vol. XVI. N° II. H 



