142 Db. Buchanan on the Fibrin contained in the Animal Fluids. 



1. Not from hlood vessels. — Some physiologists have supposed the 

 fibrinous corpuscles found in effused serous fluids to proceed from the 

 blood vessels, and have therefore named them " exudation corpuscles." 

 The large size of the corpuscles found in the blister liquid, makes it as 

 unlikely, that they sliould pass through pores in the parietes of the 

 vessels, as the red blood corpuscles which are held incapable of so 

 transuding: and it is not improbable, that there is an attractive power 

 in the tissues which retains the fibrinous particles, even when of 

 smaller size, and thus prevents transudation. 



2. Originate in situations where observed To me it appears much 



more probable that all the fibrinous corpuscles in the animal fluids, 

 whether contained in cavities or in vessels, originate in the situations 

 where they are observed. This seems to follow as a necessary con- 

 sequence from the proofs which have been mentioned above, of the 

 power which these corpuscles have of transforming themselves into 

 tissues; for such transformations prove the identity of these cor- 

 puscles with the cell-germs and cells, out of which all the tissues of 

 the body are developed. I formerly mentioned the complete resem- 

 blance which the vesicles of the blister liquid have to the blood 

 globules ; now, according to the researches of Dr. Barry, all the tissues 

 of the body originate in corpuscles not distinguishable under the 

 microscope from blood globules. It can scarcely, therefore, be doubted 

 that the fibrinous corpuscles observed in the animal fluids originate in 

 the situations in which they are observed ; where they serve, in the 

 first instance, for the development of the tissues, and subsequently for 

 their redintegration after injury. 



3. Doctrines of Schleiden and Schwann. — According to Schleiden, 

 the cell-germs of vegetables originate in the interior of the cells. The 

 only instance in which they are observed to be generated on the 

 exterior, is in the formation of the cambium, when they originate in 

 the plastic liquid interposed between the bark and the wood. Now, 

 according to Schwann, the cell-germs of animals always originate in 

 a plastic liquid of this kind, which he names the "cyto-blastema." 

 This plastic liquid he holds to exist both within the cells, and exterior 

 to them, and that in whatever situation the cell-germs are produced, 

 their origin is due to the same action of the plastic liquid. Accord- 

 ing to this view, we must look for the origin of the fibrinous corpuscles 

 we have been describing, to the liquids in which they swim. 



4. Nature of plastic liquid. — All organized bodies are developed 

 out of a liquid which presents no visible traces of organization. The 

 first step in this mysterious process appears to be the development in 

 the liquid of granules ; next these granules pass into vesicles or cells ; 

 and lastly, these cells are transformed into the tissues of the vegetable 

 and animal body. I have described, both to-night and on a former 

 occasion, a liquid derived from the human body possessing these 

 characters. It presents at first no traces of organization, but fibrinous 



