166 



August 1, 1849. 



C. T. Jackson, Vice-President, in the Chair. 



Present, twelve members. 



Dr. W. I. Burnett read a paper on the Epithehal Tissues. 



He had recently made these tissues the subject of special 

 study, having had an unusually favorable opportunity of prose- 

 cuting his researches upon numerous specimens of Epithelium, 

 obtained from the ^^ rice ivater'''' discharges of cholera patients. 

 He had been enabled to trace the development, by means of the 

 microscope, of the three forms of this tis.-^^ue, the cylinder, tes- 

 selated, and ciliated. 



Dr. Burnett entered quite at length upon the subject of the 

 cause of the motion of cilia in mucous membranes, giving an 

 account of various experiments of his own, by which he had 

 been led to the following conclusions, differing somewhat from 

 those of former observers. 



1st. If the movements of the cilia of epithelial cells are due 

 to a contractile tissue at their lower portion, this tissue is unlike 

 any other contractile tissue of the animal economy with which 

 we are acquainted. 



2d. We have no reason to suppose this tissue to be muscular, 

 because of the relative size of the cilia to the muscular fibrillae, 

 and the absence of nerves, and because electrical agencies do 

 not affect it. 



3d. We cannot consider the contractile tissue of the nature 

 of that of the Dartos, because the movements of the cilia are of 

 a uniform and rythmical character. 



4th. That, as these movements continue up to the time of the 

 death of the cell, they are intimately connected with the life of 

 the cell, considered as an individual organism. 



5th. That these ciliary motions of epithelial cells are in 

 many respects analogous to those of separate individual animals, 

 as the Infusoria, and also to those of the ova of Polyps. 



6th. That after a full consideration it is apparent that ciliated 

 epithelial cells, (spermatic particles included), although they 



