XXIII 



THE CELL-THEORY 



Brit, and For. Medico-Chir. Review, vol. xii., 1853,//. 285-314. 



Review I. 



1. De Partibtis Similaribtis. By G. Fallopius. (Date uncertain, before 1562.) 



2. Theoria Generationis. By Caspar Friedrich Wolff. 1759. 



3. Theorie von der Generation. By C. F. WoLFF. 1764. 



4. Theoria Generationis. By C; F. WoLFF. Ed. Nova. 1774. 



5. Von der eigenthilmlichen und wesenilichen Kraft der Vegetabilischen sowohl ah auch der 

 animalischen Substanz. By C. F. Wolff. 1789. 



6. Entwickehings Geschichte d. Thiere. By K. E. VON Baer. 1828. 



7. Uniersnchicngen ilber Phytogenesi^. By ScHLEIDEN. 1837. 



8. Alikroskopische Untersuchungen. By Schwann. 1838-9. 



9. Ueber das Bindegewebe. By Reichert. 1845. 

 Die Vegetabilische Zelle. By H. von Mohl. 1850. 



fie Vegetable Cell. By H. von Mohl. Translated by A. Henfrey, F.R.S. 1852. 



11. On the Mutual Relation of the Vital and Physical Forces. By W. B. Carpenter, 

 M.D., F.R.S., &c. ('Phil. Trans.') 1850. 



12. Handbuch del Gewebelehre. By A. KoLLIKER. 1852. 



If we separate the elementary and essential facts of Life from all 

 the various and complicated phenomena with which they are associated 

 among the higher forms of living beings — if we examine those lowest 

 and most rudimentary states of animal and vegetable existence, which 

 are presented to us by the so-called ' unicellular ' organisms, we find 

 that the sole definable difference between a living thing and a mere 

 formed morsel of some protein compound, fresh from the laboratory 

 of the chemist, is, that while the protein compound undergoes no 

 change which may not be traced to the immediate and direct operation 

 of some new or varying external condition, the Navicula or the 

 Gregarina passes through the most remarkable successions of form, 

 of size, and of chemical composition, which are equally definite in 

 their nature, and equally certain in the order of their occurrence, 



R 



