4^3 History of the Sexual Theory. [Book hi. 



Schleiden and Schacht on the one side and by Hofmeister on 

 the other respecting the processes in the formation of the 

 embryo. 



Gartner's writings derive their importance not so much from 

 new and surprising discoveries or brilliant ideas and un- 

 expected combinations, as from their very searching exami- 

 nation into all the circumstances and relations which can 

 come under consideration in the sexual propagation of 

 Phanerogams. His experiments in hybridisation, of which he 

 kept most exact accounts, exceeded the number of nine 

 thousand ; in these and in normal cases of pollination he 

 studied all the sources of error which could in any way affect 

 his experiments, and took into careful consideration all the 

 conditions of fertilisation connected with the development of 

 the plant itself and with its external circumstances ; at the 

 same time he examined critically all that had been written on 

 the subject, and submitted every experiment reported by 

 former observers to the test of his own wide experience. The 

 volume on self-fertilisation is a complete account of the biology 

 and physiology of flowers. The phenomena connected with 

 the unfolding and fertilisation of the flower are described from 

 the writer's own observations, some of which are quite new ; it 

 specially investigates the relations between the calyx, the 

 corolla, the secretion of nectar and the opening of the anthers, 

 also the temperature of flowers and the physiological processes 

 in the ovary, the style and the stigma; all that was then 

 known of irritability and the phenomena of movement in the 

 flower and in the organs of fructification was collected together 

 and elucidated by fresh observations, and thus a picture was 

 drawn complete to the smallest detail of the life of a flower, 

 such as we do not yet possess of any other organ. It would 

 be idle to think of giving in a small compass a clear idea of 

 the wealth of these observations. But all this was only pre- 

 liminary to the main point, the proof that Camerarius was 

 right, that notwithstanding the objections of a hundred years 



