50 HISTORY OF BOTANY 



experimental proof. Here is his conception of the process 

 of fertilisation almost in his own words : " Sulphur 

 strongly attracts air ; farina abounds in sulphur ; it is 

 placed in the movable apices of the stamina so as to be 

 easily dispersed into the air, surrounding the plant as 

 it were with a sublimed sulphureous pounce (powder) 

 which uniting with the air particles may perhaps be 

 inspired at several parts of the plant and especially at 

 the pistillum and be thence conveyed to the capsula 

 seminalis." Then follows a strange conceit : " and if to 

 these united sulphureous and aereal particles we suppose 

 some particles of light to be joined (for Sir Isaac Newton 

 has found that sulphur attracts light strongly), then the 

 result of these three by far the most active principles 

 in nature, will be a punctum saliens to invigorate the 

 seminal plant." You will note here a repetition of 

 Crew's idea, the same sulphurous material and the same 

 " vivific effluvia/' but not a word about the actual 

 fertilisation of the ovule. 



" Hales/' Sachs says, " is the last of the great 

 naturalists who laid the foundations of vegetable physio- 

 logy," but to my mind he is rather the first genuine 

 plant physiologist we meet with in the history of the 

 science. The very fact that he stands almost alone in 

 founding his conclusions on actual experiments shows 

 him to have possessed a truly scientific mind of the 

 highest order. Some of his experiments, such as those 

 concerned with the movements of sap, are quoted in 

 modern textbooks of botany, and that surely points to 

 Hales as a genius of an entirely different character to 

 those who preceded him in this branch of botanical 

 enquiry. 



LINNAEUS AND THE " SEXUAL " SYSTEM OF 

 CLASSIFICATION 



Just at the time when Hales was experimenting in his 

 vicarage garden on the banks of the Thames, a young 



