CHAP, ii.] Organs from Cesalpino to Linnaeus. 87 



was answered from the idea of it. This way of thinking is 

 found everywhere in Linnaeus, not only where he is busy as 

 systematist and describer, but where he wishes to give infor- 

 mation on the nature of plants and the phenomena of their life, as 

 in his ' Fundamenta,' his ' Philosophia Botanica,' and especially 

 in his 'Amoenitates Academicae.' From among many in- 

 stances we may select his mode of proving sexuality in plants. 

 Linnaeus knew and lauded the services rendered to botany by 

 Rudolph Jacob Camerarius, who as a genuine investigator of 

 nature had demonstrated the sexuality of plants in the only 

 possible way, namely, that of experiment. But Linnaeus cares 

 little for this experimental proof; he just notices it in passing, 

 and expends all his art on a genuine scholastic demonstration 

 intended to prove the existence of sexuality as arising neces- 

 sarily from the nature of the plant. He connects his demon- 

 stration with the dictum ' omne vivum ex ovo/ which Harvey 

 had founded on an imperfect induction, and which he evidently 

 takes for an a priori principle, and concludes from it that plants 

 also must proceed from an 'ovum,' overlooking the fact that in 

 ' omne vivum ex ovo ' plants already form a half of the ' omne 

 vivum ' ; then he continues, * reason and experience teach us 

 that plants proceed from an 'ovum,' and the cotyledons confirm 

 it'; reason, experience, and cotyledons ! Surely a remarkable 

 assemblage of proofs. In the next sentence he confines himself 

 at first to the cotyledons, which according to him spring in 

 animals from the yolk of the egg, in which the life-point is found; 

 consequently, he says, the seed-leaves of plants, which envelope 

 the ' corculum,' are the same thing ; but that the progeny is 

 formed not simply from the ' ovum,' nor from the fertilising 

 matter in the male organs, but from the two combined, is 

 shown by animals, hybrids, reason, and anatomy. By reason 

 in this and the previous sentence he understands the necessity, 

 concluded from the nature, that is, the conception of the thing, 

 that it must be so ; animals supply him with the analogy, and 

 anatomy can prove nothing, as long as it is not known what is 



