THWAITES THEORY. 413 



j)art of the contents of a pollen grain with cer- 

 tain matter contained in the ovule, and that the 

 embryo originates from this mixed matter. The 

 correctness of this opinion is rendered still more 

 probable by the consideration of what takes place 

 under the circumstances of hybridization of species. 

 The phenomena which present themselves in these 

 cases are of the highest physiological interest ; and it 

 seems imjDOSsible, after a careful consideration of them, 

 to doubt that the hybrid plant owes its existence to — 

 consists in its earliest condition of — an endochrome 

 made up of a portion of that of each of the parent 

 plants ; for the development of the hybrid embryo 

 into the mature plant indicates a quality of the con- 

 tents of this embryonic cell of a character combining 

 that of the endochrome of each of its parents. 



" The ovule of Fuchsia coccinea, fertilized with the 

 pollen of Fuchsia fulgens, produces plants of every 

 intermediate form between these two species, — some 

 of the seedling plants closely resembling one, and 

 some the other species, but the majority partak- 

 ing equally of the characters of the two plants; 

 scarcely, however, will any two be found so much 

 alike as to be undistino-uishable from each other. 

 With respect to each of the hybrid seedlmgs, sep- 

 arately considered, there is a uniformity throughout 

 in the mixed character of the various parts ; so that 

 it is easy, from the examination of the foliage, to 

 arrive at a tolerably correct idea of what will be the 



