260 SEROUS SYSTEM, 



brane. It differs from the mucous tissue in having but a 

 single layer. 



Q. What is the nature of this membrane ? 



#. It is cellular. It has the common organization of 

 the cellular tissue, without any peculiar structure; it has 

 not, for instance, any peculiar structure, such as the mus- 

 cles have in their fibrin, or as the bones have in their phos- 

 phate of lime. 



Q. What proof have you that this serous tissue is cel- 

 lular? 



t#. It is proved to be so by the identity of function and 

 that of disease; it is cellular, because it is inflated or infil- 

 trated by air; and in the process of maceration, the absence 

 of fibrous structure proves negatively the identity of the 

 serous and cellular tissues. 



Q. What gives to some parts of the body a deeper 

 black in putrefaction than others? 



t#. The blackness in putrefaction depends on the quan- 

 tity of blood in the putrefied part. 



Q. In what pathological points do the serous and cel- 

 lular tissues differ? 



<ft. In the first, being subject to a slow inflammation 

 producing tubercles, and in the circumstance that the se- 

 rous pus differs from that in the cellular texture. 



Q. What are the parts common to the serous mem- 

 branes? 



Ji. Exhalents, absorbents, and blood-vessels. 



Q. Are the blood-vessels numerous? 



Jl. No; in health they are few and small. 



Q. What shows the existence of exhalents in this tis- 

 sue ? 



/?. Expose a serous surface in the living animal, wipe 



