XOO THE HISTORY OF BIOLOGY 



account, so that plants which resemble one another are grouped together 

 although the seeds are different. Above all, he reminds us that nature never 

 makes any jumps; on the contrary, the extremes are connected by middle 

 forms, just as the zoophytes come between the vegetable and animal king- 

 doms. In regard to the anatomy of plants, in all essentials Ray follows Mal- 

 pighi; Grew's ideas on the sexuality of plants are also accepted, without, 

 however, being further developed; Ray was ignorant of Camerarius's obser- 

 vations. On the other hand, he describes the germination of plants, making 

 original observations of considerable value; the difference between plants 

 with one and those with two cotyledons was established by him. Ray 

 discussed the notion of species more thoroughly than any previous biolo- 

 gist. In his view, plants belong to the same species if they give rise through 

 their seed to a new plant similar to themselves, in the same way as bulls 

 and cows are the same species because in mating they produce creatures 

 which resemble themselves. The number of species is invariable, for God 

 rested on the seventh day from all his work — that is, from creating 

 new species. On the other hand, the different-coloured flowers in plants 

 should not be regarded as separate species, any more than the different- 

 coloured calves born of cows; in the former this is proved by the fact that 

 the colour variations are not reproduced through seed, but only through 

 cuttings. The invariability of species is, however, not absolute; plant species 

 can be varied through the "degeneration" of the seeds — thus it has cer- 

 tainly occurred that the seed of the cauliflower has produced leaf-cabbage 

 and that from the seed of frimula veris t?iajor has arisen primula fratensis in- 

 odora. Ray even includes in the discussion a number of ancient stories as to 

 grain's having degenerated into weed: wheat to Lolium and maize to other 

 kinds of weed. True, he doubts the truth of a number of these statements, 

 but he nevertheless believes the thing to be possible. This belief of his in 

 the variability of species has been cited as proof of an unprejudiced view, in 

 contrast to the theory that arose later as to the absolute constancy of species. 

 The examples quoted rather go to show clearly enough that Ray was unable 

 to rid himself of a certain amount of primitive superstition. 



As far as actual classification was concerned, Ray retained the division 

 into herbs and trees, or, more correctly, herbaceous plants and ligneous 

 plants, maintaining that the latter are differentiated from the former by the 

 existence of winter buds — in actual fact, an incorrect assumption. In a later 

 edition of his Methodus, however, influenced by Rivinus, he abandoned this 

 division. Herbs are then divided into: tm-perfecta (fungi, alga;, lichens, and 

 corals) and perfect a (plants bearing flowers, which are again divided intu 

 those having tw^o and those having one cotyledon). The sub-groups under 

 these categories are numerous, some natural and well characterized, others 

 composed of all sorts of plants, massed together owing to some purely ac- 



