106 REPORT— 1870. 



of degeneration or even of equal oscillations to and fro, but of a movement which, 

 in spite of frequent stops and relapses, has on the whole been forward ; that there 

 has Deen from age to age a growth in man's power over nature, which no degrad- 

 ing influences have been able permanently to check." 



I must not trespass into the province of the botanist, but I should be glad to 

 say that no easier method of learning how the natural-history sciences can be made 

 to bear upon the history of man, as a whole, can be devised than that furnished by 

 the perusal of such memoirs as those of Unger's upon the plants used for food by 

 man. The very heading and title of the paper I am specially referring to appears 

 to me to have an ambiguity about it which, in itself, is not a little instructive. In 

 that title, "Botanische Streifziige auf dem Gebiete der Cultur-Geschichte," the 

 latter word may be taken, I imagine, etymologically at least, to refer either to cul- 

 ture proper, or to floriculture, or to agriculture. At any rate, the paper itself 

 may be read in the Sitzungsberichte of the Vienna Academj^ for 1859 ; it has, I 

 suppose, superseded the interesting chapters in Link's ' Urwelt und Alterthum,' 

 of date 1821 ; and it is not unlikely, I apprehend, to be itself, in its turn, super- 

 seded also. 



Coming, in the third place, to Zoology, I suppose I shall be j ustified in saying 

 that the largest issue which has been raised in the current year, an issue fur the 

 examination of the data for deciding wliich the two months of July and August 

 which are just past may have furnished persons now present with opportunities, 

 is the question of the Irinship of the Ascidians to the ^^ertebrata. There is or 

 was nothing better established tiU the appearance of Kowalcwsky's paper, now 

 about foiu" years ago, than the existence of a wide gulf between the two great 

 divisions of the animal kingdom, the Vertebrata and the Invertebrata : notliiug 

 could be more revolutionary than the views which would obviously rise out of his 

 facts ; and within the present year these facts have been abundantly confirmed by 

 Prof. Kupfer, whose very clearly written and beautifully illustrated paper has j ust 

 appeared in the current number of Schultze's ' Arcliiv fiir niicroscopische Aua- 

 toniie.' Kupfer's researches have been carried on upon Ascidia canina ; but they 

 more than confirm the accuracy of what Kowalewsky had stated to take place in 

 Ascidia mammillata, and which may be summed up briefly thus : — In tlie larval 

 Ascidian we have in its caudal appendages an axis skeleton clearly analogous, if 

 not essentially homologous, to the chorda dorsalis of the vertebrate endsryo, as con- 

 sisting, like it, of rows of internally placed cells, and giving insertion by its sheath 

 to muscles. We have further the nervous system and the digestive taking up in 

 such embryos much the same positions relatively to each other, and to this mol- 

 luscan chorda dorsalis, that are taken up by the confessedly homologous system in 

 the Vertebrata ; we have the nervous system originating in the same fashion and 

 closing up like the vertebrate myelencephalon out of the early form of a lamellar 

 furrow into that of a closed tube ; we have, finally, the respiratory and digestive 

 inlets holding the vertebrate relationship of continuity with, instead of the inver- 

 tebrate of dislocation and separation from, each other. Such are the facts ; but I 

 am not convinced that they will bear the interpretation that has been put upon 

 them ; though I nmst say the possession of this chorda dorsalis by the active loco- 

 motor larva of the Ascidian which one day settles down into such immobility 

 lends not a little probability to Tsiv. Herbert Spencer's view of the genesis of the 

 segmented vertebral column in animals undoubtedly vertebrate. But on this view 

 I should not be inconsistent with myself, inasmuch as, to waive other considera- 

 tions, the chorda dorsalis in each case would be considered as an adaptive or teleo- 

 logical modification, not a sign of morphological kinship*. Much perplexity may 

 or must arise here ; and whilst entertaining these views, I felt myself bound to ex- 

 amine myself strictly to find whether in not taking them up, I might not be giving 

 way to that reactionary reluctance to accept new ideas which advancing years so 

 frequently bring -^^ith them ; but a recent paper, by Lacaze-Duthiers, published in 

 the 'Coraptes Rendus' for May 30, 1870, and translated in the 'Annals and Magazine 

 of Natm-al History ' for July 1870, woidd justify me, I think, in calling that reluc- 



* See, however, Mr. Herbert Sjiencer's Appendix D to his principles of Biology, pt. iv. 

 chap. xvi. This appendix was printed in 1865, but not published till December 1869. I 

 had not seen it when I wrote as above. 



