May 16 1H(I2.] 



SCIENCE. 



795 



usally large number of species, and are very 

 abundant. Certainly the Pacific Coast botan- 

 ists are to be congratulated upon having two 

 such excellent stations for study and research. 



MULTIPLICATION OF SPECIES IN BOTANY. 



It is never safe to 'call a halt' in any de- 

 partment of science, much less in a department 

 in which one is not himself a specialist; yet 

 such non-specialist may be permitted to give 

 his impressions as an interested on-looker from 

 another part of the field. And as it often hap- 

 pens that the soldier in a different part of the 

 field of battle is able to see more clearly what 

 is taking place than those in the thick of the 

 melee, so it may be that botanists just a little 

 outside of the work of descriptive systematic 

 botany are able to measure the real value of 

 some of the work now being done. One can 

 hardly take up a botanical journal without 

 finding that some of the common species of 

 plants have been split into two or more forms 

 called 'species' by their authors. That such 

 work must be done is inevitable, but it is in- 

 credible that ten to twenty species should have 

 been able to hide themselves in plants which 

 had been critically studied by such masters as 

 Gray, Torrey and Watson. As long as these 

 leaders were found to have confused only two 

 or three species in one the interested on- 

 looker was ready enough to accept the dictum 

 of present-day specialists in single genera, and 

 to admit that the masters had blundered, but 

 when we are asked to believe that Gray and 

 Torrey were totally blind and incapable of 

 seeing or defining the limits of species, it is 

 evident that these later workers are dealing 

 with something of which their predecessors 

 either knew nothing or cared nothing when 

 they were defining species. In 1878 there were 

 catalogued for North America in Watson's 

 Bibliographical Index 14 species and 10 varie- 

 ties of hawthorns, of the genus Cratcegus. In 

 1899 these numbers had risen to 34 species and 

 11 varieties. To-day we are asked by several 

 botanists to add to this list 225 new species 

 almost entirely from the eastern United States, 

 where three years ago there were not one tenth 

 as many! 



Of course this brings up the old question of 



the limits of species. This can not be dis- 

 cussed in a short note, but this is certain, that 

 in the case cited we are asked to give greater 

 values than formerly to observable variations. 

 This is carried to such an extreme that one is 

 compelled to ask whether this change is war- 

 ranted. Are not these new species merely local 

 variations, or in some instances individual 

 variations? The ornithologists have noticed 

 similar minute variations in birds, although 

 they have not regarded them as specific, but 

 rather varietal, or sub-varietal. Yet there are 

 ornithologists who question the wisdom of re- 

 quiring that all members of a particular sub- 

 variety should have been taken 'under the 

 same blackberry bush.' Are not the botanists 

 who are making so many species open to a sim- 

 ilar criticism ? If in Cratcegus we have species 

 with such slight variations, what are we to do 

 with the varieties of the common apple trees? 

 We shudder at the thought of these species- 

 multipliers getting into our orchards. There 

 must be ai least a thousand or so good 'species' 

 hidden in Pirus malus of Linnssus ! 



Charles E. Bessey. 

 The University of Nebraska. 



TEE COLLECTED PHYSICAL PAPERS OF 

 HENItY A. ROWLAND. 



A volume containing the physical papers of 

 Professor Henry A. Rowland, for twenty-five 

 years professor of physics in the Johns Hop- 

 kins University, is now in preparation. It 

 will be issued under the editorial direction of 

 a committee appointed for that purpose, con- 

 sisting of President Remsen, Professor Welch 

 and Professor Ames. The book will contain 

 Professor Rowland's articles and memoirs on 

 physical subjects, together with his popular 

 writings and addresses, numbering sixty in all. 

 These have been collected from over twenty 

 different magazines and journals. The sub- 

 jects treated in these papers cover a wide 

 range. In heat there is the great memoir on 

 the mechanical equivalent of heat, with several 

 shorter articles on thermometers. In electricity 

 and magnetism there are the fundamental re- 

 searches on magnetization, on the magnetic 

 effect of electrical convection, on the value 

 of the ohm, on the theory and use of alterna- 



