These four substances may be considered as real organic elements, 

 since with our means of analysis, we never can succeed in converting any 

 of these substances into another. The cerebral pulp is not convertible 

 into a horny substance, into cellular substance, or into muscular fibre, 

 neither can any one of these tissues ever be converted into cerebral pulp. 

 The bones, the cartilages, the ligaments, the tendons, the aponeuroses, 

 may, by long maceration, be converted into cellular substance. Muscu- 

 lar fibres are not subject to that alteration, nor is the nervous or cerebral 

 pulp : the horny substance also resists that change. Every thing, there- 

 fore, leads us to acknowledge these four constituent principles in our 

 organs. 



The primitive or simple tissues, variously modified, and combined in 

 different quantities and in various proportions, constitute the substance 

 of our organs. Their number is much more considerable, according to 

 Bichat, whose happiest conception was the analysis of the human or- 

 ganization. This physiologist reckoned in the human oeconomy, no few- 

 er than twenty-one general or generating tissues*. But it is evident, 

 that this analysis is carried too far; that the tissues of which the skin 

 and the hair are formed, are exactly of the same nature, are analagous 

 in their properties, and are nourished in a similar manner ; that the cel- 

 lular tissne is the common basis of the osseous, cartilaginous, mucous, 

 serous, synovial, dermoid, &c. 



It must be confessed, that this separate consideration of each organic 

 tissue has furnished him with new ideas, ingenious analogies, and use- 

 ful results, and that his " Anatomic Generate," in which those research- 

 es are contained, is his chief title to glory. That glory would be com- 

 plete, if in that book, and yet more, in his other works, he had done his 



USE according as more or less of either kind of nervous substance enter into its compo- 

 sition. An intimate view of the mode of distribution which characterizes both class of 

 nerves, as well as various other considerations, support this opinion, which is calculated 

 to form the basis of some plausible explanations of many of the most important appear- 

 ances and functions of the different muscular textures. 



* The following classification of the primary and compound textures nearly coincides 

 with that recommended by Dupuytren and Magendie : 



fl. Cellular. 



3. Muscular 



r Arterial. 



4. Vascular. . . . . . <Veinous. 



Lymphatic. 



5. Osseous. 



f" Fibrous. 



6. Fibrous , . . < Fibro-Cartiluginous. 



Dei-moid. 



7. Erectile. 



8. Mucous. 



9. Serous. 

 10- Synovial. 

 11. Glandular. 



^.12. Epklermous. or Corneous. Copland, 



