Septejibee 20, 1895.] 



SCIENCE. 



369 



inherent factors promoting and restricting 

 their development, including the reciprocal 

 influence of proximity. Of the names promi- 

 nent in this connection, those of Coville, Tre- 

 lease and MacMillan are especially worthy 

 of mention . The last has done good service 

 by calling attention to the significance of 

 tension lines, in his account of the ' Metas- 

 permse of the Minnesota ValleJ^' There is 

 a phase of phylogenetic study which has 

 received some attention of late, in form of 

 the breeding of plants. It is a subject 

 especially adapted to experiment station 

 work. The leader in this line of research, 

 L. H. Bailey, has also materially promoted 

 ecological studies by his numerous bioge- 

 netic and other writings. 



Coming to phj^siology, sensu stricto, we 

 find the domain of the science so well de- 

 fined and its several areas so well cultivated 

 that a clear statement of its main problems 

 is now possible. ISTot much advancement 

 was made before the beginning of the present 

 century. The most notable achievements 

 had been the publication of Hales' brilliant 

 work on the pressure and movement of sap, 

 which introduced the physical side of physi- 

 ology to the world, and Ingenhousz's 

 equally entertaining volume upon his dis- 

 coveries regarding the uses of green organs, 

 which introduced the chemical side of physi- 

 ology to the world. The century was 

 ushered in by Knight's classical essays, in 

 which it was pointed out, among other 

 things, that there was a substantial reason 

 why roots grow downward and stems up- 

 ward, and by De Saussure's researches upon 

 respiration and other chemico-physiological 

 matters. It is worth mention that Hales, 

 Ingenhousz, Knight and De Saussure were 

 not botanists, although they cultivated 

 botanical subjects; neither were Senebier, 

 Du Hamel, Dutrochet, Liebig, Boussingault 

 and others, who assisted in laying the 

 foundations of the science, but were physi- 

 cists, chemists and horticulturists. And to 



this day much important data is contributed 

 to the science by workers in other fields. 



Thus facts accumulated, important dis- 

 coveries were made, and the mysteries of 

 the life processes in plants were gradually 

 unfolded. But it was not until 1865 that 

 the science was given the commanding po- 

 sition due to it. Then appeared the first 

 treatise which set forth the phenomena and 

 laws of vital processes with due regard to 

 proportion, and with clear philosophical 

 insight. Sachs, in his ' Experimental 

 Physiology,' became the founder of the sci- 

 ence in its modern aspect. He set forth 

 with critical discrimination the most im- 

 portant matters pertaining to the organ- 

 ism's relation to light, heat, electricity and 

 gravity, the processes of metabolism, nutri- 

 tion and respiration, and the movement of 

 water and gases in the plant. With rare 

 foresight he excluded all, or nearly all, 

 topics not strictly belonging within the true 

 scope of the science, and presented the 

 whole subject-matter in an entirely original 

 form, breaking away from the customs of 

 his predecessors and adopting advanced 

 scientific methods. It was an epoch-making 

 book. As Strasburger has recently said in 

 his history of botany in Germany, " the 

 work at once restored vegetable physiology 

 to its place at the center of scientific re- 

 search." 



The book has never been translated into 

 English, and so, while it stimulated the 

 study of physiology in Germany, and phy- 

 siological laboratories soon became common, 

 led by the famous one at Wiirzburg, pre- 

 sided over by Sachs, American botany felt 

 little of the new movement until the ap- 

 pearance of Sach's ' Text-book ' in English 

 dress a decade later. Even then the new 

 science (for such it was in America) gained 

 but an insecure footing. After another 

 decade, in 1885, appeared the first, and to 

 the present the only, treatise on physiolog- 

 ical botany by an American author. This 



