24 THE CELL DOCTRINE. 



Prochaska * in 1779, described the brain as made 

 up of globules eight times smaller than blood-glob- 

 ules. In the year 1801, the philosophic mind of 

 Bichat elaborated his excellent classification, but he 

 seems to have made no original investigations in 

 minute structure, or to have adopted any special 

 theory of an ultimate physical element. The bro- 

 thers, Joseph and Charles Wenzel,t in 1812, de- 

 scribed the brain as composed of, globules of small 

 size. Among the earliest histologists worthy of 

 mention, is Treviranus,:]: whose elements, according 

 to Ilenle, were first, a homogeneous, formless matter ; 

 second, fibres; third, globules (kiigelchen). Mr. 

 Bauer,§ quoted as a most experienced microscopic 

 observer by Sir Everard Home, in 1818, and again 

 in 1823, described the ultimate globules of the brain 

 and of muscular fibre as of the size of a globule of 

 blood when deprived of its coloring matter, or about 

 j-jjig^ of an inch in diameter. The fibre was excluded 

 as an ultimate element of organization by Heusingeri 

 in 1822-4, who started all tissues from the globule, 

 still, however, retaining the formless material of 

 Haller and Treviranus. Heusinger formed the fibre 

 by the linear apposition of his globular elementary 

 parts, and even explained how canals and vessels 

 were formed by a similar arrangement of vesicles 

 which had originated from the globules. The ac- 

 count given by Henlel" of the method in which Heu- 



* Proschaska, Opera Minora, Part I, p. 342 



■j- Wenzel, op. citat., p. 24. { Treviranus, op. oitat. 



g Bauer, op. citat. || Heusinger, op. citat., p. 112. 



I' Henle, Allgemeine Anatomie. Leipzig, 1841, p. 128. 



