368 Dr. A. Brann on the Vegetable Individual. 



vi duals, as pointed out by the doctrine of shoots, within the 

 limits of vegetable species, will no longer surprise us ; on the 

 contrary, it will open to us a deeper insight into that independ- 

 ence presented to us even in the life of nature, in the realization 

 of the internal problems of the creation. 



But here, too, as is so variously the case in nature, the regu- 

 lative law is admirably united to the free contiguration ; for what 

 gives a peculiar interest to the differences among shoots in the 

 same species is the regular reciprocal relation among the shoots, 

 as they reciprocally complete each other by their very one-sided- 

 ness, and thus form a higher whole. In this respect the quali- 

 tative difference of shoots bears a certain relation to their origin, 

 that is, to the order of ramification to which they belong. And 

 as the formation of shoots, as was shown, is a process of propa- 

 gation, we see here, in the history of the development of the 

 species, propagation taking the place of individual development. 

 A second individual takes up the thread of reproduction which 

 the preceding one was unable to carry any farther. Thus, what 

 we are accustomed to see elsewhere attained in the individual, is 

 here reached by the generation in a more or less strictly deter- 

 mined cycle; — in other words, where the single shoot is inca- 

 pable, a determinate succession of shoot-series arises to bring the 

 internal problem of its existence to a consummation, — to com- 

 plete the metamorphosis into flower and fruit. This remarkable 

 phsenomenon, — which is a very frequent one in the vegetable 

 kingdom, and is one of the essential characteristics of many of 

 the most important families of plants, e, g. the Grasses, Synan- 

 theredBj Labiatiflorece, Crucifera, Leguminosce, &c., — is the same 

 as that which in the animal kingdom (in whose lower orders it 

 reappears) was, we cannot say discovered, but brought to a 

 clearer comprehension not long since by the Norwegian natu- 

 ralist Sars*, completed and confirmed by Von Siebold^s investi- 

 gations into the history of the development of Medusa auritaf, 

 and soon after substantiated in its universality by the Dane, 

 Steenstrup, under the name of " alternation of generation,*' or 

 propagation and development by alternate series of generations J. 

 Single cases of alternation of generation had been already care- 

 fully observed § ; but they were too much in opposition to the 



* In Wiegmann's Archiv, 1844, where the observations pubUshed in the 

 author's earlier works, on the adolescent states of Medusa, are completed 

 and concluded. 



t Beitrage zur Naturgesch. der wirbellosen Thiere. Danzig, 1839. 



X Ueber d. Generationswechsel, iibersetzt von Lorenzen, Copenhagen, 

 1842. 



§ Bonnet's industrious observations, the first that were made, of the 

 alternating mode of reproduction of Aphis, published in his * Traite de 



