162 



SCIENCE. 



[N. S. Vol. V. No. 109. 



more than any other directly useful in the 

 study of the phenomena of the cycle, both 

 in ontogeny and phylogeny, may be briefly 

 noticed as follows : 



The opinion that the higher animals are 

 complex, colonial aggregates of cells, which 

 in structure are equivalents to the lowest 

 and minutest adult forms of the animal 

 kingdom, the unicellular bodies of Protozoa, 

 has been steadily gaining in probability 

 since it was first announced by Oken in 

 1805, in ' Die Zeugung,' Frankfurt bei 

 Wesche, 8vo. This work we have not yet 

 seen, but in the first edition of the Natur- 

 philosophie, Jena, 1809, II., XII. Buch, 

 Zoogenie, he describes protoplasm as 

 ' Punktsubstanz ' and as giving rise to the 

 ' Blasenform or Zellform' in both animals 

 and plants. Oken considered the lower 

 animals ' Polypen, Medusen, Beroen, kurz 

 alle Gallertthiere ' to be composed of 

 Punktsubstanz.' The nerves, the cartilage, 

 bones of higher animals, were considered as 

 modifications of this form of ' protoplasm,' 

 but the skin and fleshy parts, including the 

 viscera, were described as cellular, ' dem 

 Fleisch liegt die Blaschenform zu Grunde;' 

 again on p. 30, ' die Eingeweide welche am 

 meisten a us Zellengewebe bestehen.' Oken 

 in XII., VIII. Buch, treats of the subject 

 we are more immediately interested in 

 and writes as follows : " Pflanzen and 

 Thiere konnen nur Metamorphosen von 

 Infusorien sein," " im kleinsten sindsie nur 

 infusoriale Blaschen die durch verschiedene 

 Combinationen sich verschieden gestalten 

 and zu hoheren Organismen aufwachsen," 

 and also adds on p. 29, in anticipation of 

 one of the points advanced by the author 

 in his ' Larval Theory of the Origin of 

 Cellular Tissues,'* ' auch besteht der Samen 

 aller Thiere aus Infusorien.' 



This author directly compares his cystic 

 or intestinal animals, Infusoria, with ova, 



*Proc. of the B. S. N. H., Vol. XXIII., March 5, 



1884. 



and speaks oi them as oozoa, and in the 

 preface to the English edition of his 

 Physiophilosophy, Lond. 1847, Roy. So- 

 ciety, he writes that all organic beings 

 originate from and consist of vesicles or 

 cells. " Their production is nothing else 

 than a regular agglomeration of Infusoria ; 

 not, of course, of species previously elaborated or 

 perfect, hut of mucous vesicles or points in general 

 ivhich first form themselves by their tmion or 

 combination into particular species." Oken's 

 view was based on the resemblances exist- 

 ing between the Protozoa and the cells 

 in the tissues of the Metazoa, and it is evi- 

 dent he is entitled to be considered the first 

 teacher of the unicellular doctrine, an honor 

 now universally given to von Siebold. 



However imperfect and imaginative the 

 results as compared with the more objective 

 statements of later observers, the author 

 who wrote such sentences as these had as 

 clear ideas as the knowledge of his time per- 

 mitted and was the Haeckel of the early 

 part of this century, and like him a great 

 and successful leader, making many errors 

 but also many discoveries and ' blazing out ' 

 some of the paths that we are still fol- 

 lowing. 



Meckel* seems to have been the first au- 

 thor who brought together and stated in a 

 clear way the scattered observations and 

 ideas with regard to the correlations exist- 

 ing between the transient stages of devel- 

 opment of the individual and the so-called 

 permanent modifications represented by 

 the similar characters in the adult stages 

 of similar forms. 



Meckel says: " Es giebt keinen guten Phy- 

 siologen, den nicht die Bemerkung frappirt 

 htitte, dass die urspriingliche Form aller 

 Organismen eine und dieselbe ist, und dass 



* Meckel. ' Entw. e. Darstellung der Embryonal- 

 zustiinde d. hoheren Thiere u. d. Perman. d. zn d. 

 niedern stattfindenden Parallele.' Beitr. z. vergeich. 

 Anat., II., Leipzig, 1811, pp. 1-148; Jleokel speaks 

 of his publications as only preparatory to more ex- 

 tended researches. 



