PUS. 99 



only secreted imperfectly, and consequently we meet with 

 cells in every state of development under these circumstances. 

 These changes in the epithelium lead to corresponding variations 

 in the fluid portion of the mucus, for if a normal stratum of 

 epithelium is no longer formed, that is to say, if the deeper 

 layers throw off the superior cells before they have arrived at 

 maturity, the changes impressed on the fluid must be different 

 from those which it would undergo during the ordinary secre- 

 tion of healthy mucus. It is impossible that all the nutritious 

 matter of this fluid can be consumed by these immature cells, 

 and we consequently find in it, under these circumstances, a 

 greater or less quantity of albumen and fat, two substances which 

 universally yield a cytoblastema for the higher development of cells. 



If an increased secretion of mucus takes place on a mucous 

 membrane which possesses only a single layer of epithelium, 

 (either the cylinder or the ciliated variety,) the mucus-corpuscles 

 appear immediately after the epithelium has scaled off. The 

 transition of the mucus-corpuscles into epithelium-cells is not 

 observed so well in this instance, as when there is a profuse 

 secretion from a surface possessing several layers. These 

 transitions and various stages of development lead us to the con- 

 clusion that the mucus-corpuscles represent the first stage of 

 formation of the epithelium- cells, into which they would ulti- 

 mately have been converted if they had not been thrown off too 

 early, and, further, that the different forms of epithelium-cells 

 are in their primary state identical with one another. 



The same elements are likewise recognised, according to 

 Henle, in other tissues, in the ganglia of nerves, in the brain, 

 in the contents of the Graafian vesicle around the ovum, in the 

 parenchyma of the liver, and in the blood-formative glands, (the 

 spleen, thymus, and thyroid.) These cells occur also in the 

 blood, where I have termed them chyle-corpuscles ; they proba- 

 bly represent the blood-corpuscle in a preparatory stage of de- 

 velopment. 



If we suppose the secretion of mucus to be still further in- 

 creased, the mucous membrane will produce only these primary 

 cells, which cannot be distinguished from pus-cells, with which, 

 in fact, they are identical. Whether the secreted fluid is to 

 be regarded as pus, mucus, or purulent mucus, depends on the 

 quality of the liquid that is secreted with the cells. If it con- 



