414 History of the Sexual Theory. [BOOK in.

plants were at that time often regarded on insufficient grounds as true seeds ; G�rtner distinguished them from seeds, because they are formed without fertilisation and yet are capable of germination, whereas ovules become seeds capable of germina- tion only under the influence of the pollen. He distinctly denied the sexuality of the Cryptogams ; it was not till fifty years later that strict scientific proof was substituted in this department of botany for vague conjecture, and it was more in the interest of true science in Gartner's day to deny sexuality in the Cryp- togams altogether, than to take the stomata in Ferns with Gleichen, or the indusium with Koelreuter, or the volva in Mushrooms for the male organs of fertilisation. G�rtner rightly appealed to Koelreuter's hybrids against the defenders of the theory of evolution; and to those who saw in the seed only another form of vegetative bud, he said, that the bud can produce a new plant without fertilisation but that the seed cannot. We have already given an account in the chapters on Systematic Botany of the services rendered by G�rtner to the knowledge of the seed in its immature and in its mature condition ; as regards the process of fertilisation he adopted in the main Koelreuter's view, that it is the result of the union__ of a male and female fluid, from which the germ-corpuscle in the ovule is developed by a kind of crystallisation. Konrad Sprengel also fully committed himself to this view, and was thereby prevented from understanding the process of fertilisa- tion in Asclepiadeae.

In KONRAD SPRENGEL 1 we encounter once more an observer

1 Christian Konrad Sprengel, born in 1 750, was for some time Rector at Spandau. There he began to occupy himself with botany, and devoted so much time to it that he neglected the duties of his office, and even the Sunday's sermon, and was removed from his post. He afterward lived a solitary life in straitened circumstances in Berlin, being shunned by men of science as a strange, eccentric person. He supported himself by giving instruction in languages and in botany, using his Sundays for excursions, which any one who chose could join on payment of two or three groschen.

He met with so little support and encouragement that he never brought out