512 



SCIENCE 



[N. S. Vol. XXXIX. No. 1005 



considerable basis for the more fundamental 

 researches that prevail at the present time, 

 while plant physiology, on the other hand, has 

 come to the study of cell phenomena largely 

 without passing through this stage. Electro- 

 physiology plays but a very subordinate role 

 in plant physiological texts, and refined quan- 

 titative studies of the grosser movements of 

 the plant have never had great vogue. It is 

 in just this general field that Bose's writings 

 lie, and his results, while not calculated now 

 to arouse great interest per se, must be taken 

 into serious account and will doubtless throw 

 valuable indirect light upon the more funda- 

 mental lines of study now mainly attracting 

 attention. 



The author makes, at the very beginning 

 of the book before us, a suggestion which has 

 great possibilities in physiological research. 

 "Is there any means by which we might find 

 out whether a given influence has contributed 

 to the plant's well-being or the reverse, 

 whether it has left it more or less excitable,'" 

 etc. ? " The relation between the stimulus and 

 the response would thus form a gauge of the 

 physiological condition of the organism " 

 (pages 1 and 2). In physiological terms, the 

 tone of the organism as a whole is here in 

 question, and the quantitative relations be- 

 tween stimuli and response are to be drawn 

 upon as measurements of tone. ISTow, it is just 

 this matter of the physiological condition of 

 organisms for the estimation of which we 

 most require objective methods; it has been 

 the practise of students of plant physiology to 

 define their organisms in the terms of the 

 older descriptive work, assuming, for exam- 

 ple, that a number of given plants are the 

 same thing physiologically because they ex- 

 hibit the same superficial shapes, sizes, etc., 

 to the taxonomist. Two workers may employ 

 the same species or variety in the taxonomic 

 sense, but their organisms may be very differ- 

 ent physiologically and they may disagree en- 

 tirely on the sort of response attained with 

 a given stimulus or set of environmental con- 

 ditions. If some of the dimensions or char- 

 acteristics of the internal condition of the 

 organism used in an experiment could be 



measured and stated, much would be done to 

 avoid many of the wasteful arguments which 

 so often diminish the efficiency of physio- 

 logical workers. From Bose's suggestion it 

 appears to the reviewer that the methods of 

 the present work may be of value in the 

 physiological definition of our plant subjects, 

 just as similar methods in animal physiology 

 are proving of value to medical diagnosticians. 



The subject-matter of this book defies use- 

 ful treatment in a review. A few statements 

 may, nevertheless, be made here. Most of the 

 study has to do with the familiar paratonic 

 movement of the leaf of Mimosa, though other 

 organs receive attention at particular points. 

 To obtain an automatic graph ("phytogram" 

 or " plant script ") of this response, a thread 

 is attached to the petiole and to a light bent 

 lever above, the latter counterbalanced and 

 carrying a writing point which moves over a 

 smoked surface. A glass plate, allowed to 

 fall by clock work, furnishes the receptive 

 part of the apparatus. To avoid too great 

 friction it was found necessary to make the 

 recording point vibrate in a plane at right 

 angles to the receiving plate, and it was pos- 

 sible to arrange the vibrations so as to mark 

 time. Thus a record with this " resonant 

 recorder " appears as a line indicated only by 

 a series of dots on the smoked surface, the 

 distances between the dots indicating small 

 units of time. The apparatus is so ingenious 

 and delicately efficient as to excite wonder 

 and admiration in and for itself. Stimuli of 

 several kinds are employed, applied to the 

 leaf in various ways. The most frequently 

 used are thermal (obtained electrically, so as 

 to be quantitatively controlled) and electric. 

 The graphs show a short latent period, a period 

 elapsing between beginning and end of the 

 fall of the leaf (" apex time ") and a long 

 recovery period. Besides these three time 

 periods is of course to be considered the am- 

 plitude of the movement, in characterizing the 

 nature and intensity of the response. 



Some of the topics experimentally dealt 

 with are the following — the terms themselves 

 show the parallelism between the plant phe- 

 nomena here described and the familiar ones 



