OF THE ORGANS. 87 



86. In admitting with Haller the existence of three sim- 

 ple organs, of three elementary tissues, or of three distinct 

 fibres, distinguished from each other by essential characters, 

 viz : the cellular tissue, the muscular fibre, and the medullary 

 or nervous substance, we have not even then arrived at the 

 last point that can be attained by anatomical analysis. By the 

 aid of the microscope, we see that these simple organs, with 

 all their modifications and compounds, can be reduced to two 

 anatomical elements. They are formed, of an areolar permea- 

 ble animal substance and of microscopic globules, similar to 

 those found in the humours. The first substance alone forms 

 laminae and most commonly fibres, differing from each other 

 only in the filiform and elongated figure in the first case, widen- 

 ed in the second, and which though sometimes separated, are 

 oftener united : it is from their reunion that result the cells 

 or the areola3, &c. This first element, which by itself, though 

 variously modified, constitutes the greater part of the organs, 

 united with the other, whose particles it assembles and joins, 

 forms the muscular fibre and the nervous substance. 



87. The organs also differ, one from the other, in the phe- 

 nomena they present during life, and which will soon be con- 

 sidered. It will suffice here, to observe, that the cellular 

 substance is particularly remarkable for its continued contrac- 

 tion, which can be augmented by impressions or irritation ; 

 that the ligamentous and elastic tissues, its two principal va- 

 rieties are noted, the one for its great tenacity, and the other 

 for a great elasticity; that the muscular fibre is, by its contrac- 

 tion, the organ of all the great motions and that the nervous 

 substance is distinguished from all others by the faculty of 

 conducting all impressions to the centre, and the action of the 

 nervous centre to the muscles, &c. 



88. The organs differing from each other in their con- 

 formation, their texture, their physical properties, their che- 

 mical composition, and during life in the action they produce, 

 have been divided into a certain number of classes or genera. 

 These genera should be determined from the whole of the 

 characters taken together, and not from the form only j other- 



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