810 



SCIENCE 



[N. S. Vol. XXX. No. 779 



the entire development becomes affected, that is, 

 functional adaptations are transmissible. 



James Eollin Slonaker 

 Leland Stanfoed Junior University 



Ejfects of the Bays of Eadium on Plants. By 



Charles Stuart Gagee. Memoirs of the 



New York Botanical Garden, Vol. IV., 1908. 



Imp. 8vo, viii + 278 pages, Y3 figures and 



14 plates. Price $2.00. 



As known to several botanists, the author 

 was engaged for some time in studying the 

 effects of radioactivity on various plant proc- 

 esses. The present volume represents the sum 

 and substance of approximately four years of 

 labor and is presented as a pioneer investiga- 

 tion; comprehensive in scope and as offering 

 initial suggestions for several important prob- 

 lems. 



During the research period " standard prepa- 

 rations of the purest radium bromid yet ob- 

 tained " were placed at the disposal of Dr. 

 Gager by Mr. Hugo Lieber, of New York City. 

 As a result of the cooperation of liberality and 

 investigation we may now feel quite certain 

 that the rays of radium constitute a stimulus 

 to the metabolic processes in plants. In con- 

 formity with other stimuli, that of radio- 

 activity exhibits a minimum, optimum and 

 maximum. Metabolic processes in general, 

 whether constructive or destructive, are accel- 

 erated by intensities of stimulation between 

 the minimum and optimum, while greater in- 

 tensities beyond the optimum retard until 

 death follows at the maximum. 



Looking more particularly at the individual 

 topics treated, we find an initial chapter of 

 fourteen pages which constitutes a digest of 

 about one hundred and fifty citations. In 

 clear and rather popular style the essential 

 facts of the nature of radioactivity are pre- 

 sented. 



The universal presence of radioactivity in 

 soil, water, rain, snow, etc., is elaborately dis- 

 cussed and the obvious deduction drawn that 

 living matter can hardly escape its influence. 

 Such being the case, any sudden change in the 

 intensity of the emanations would be expected 

 to constitute a stimulus to the exposed or- 

 ganisms. 



Quite appropriately some attention is given 

 to the undemonstrated conclusions of various 

 authors regarding radioactivity as a property 

 of wood, flowers and other plant organs. The 

 unsuccessful efforts to artificially create life 

 through the influence of radium are explained. 

 An historical review of previous work done on 

 both plants and animals occupies several pages. 



The power of radium to affect the germina- 

 tion of seeds and the subsequent growth of the 

 seedlings is clearly shown by the author's ovm 

 work. A given plant can be educated, so to 

 speak, to endure an intensity of stimulus 

 which on first exposure retarded growth. This 

 shows that since radioactivity is so universal 

 in nature that plants are probably naturally 

 attuned to at least a low intensity which may 

 be gradually increased without disturbing the 

 normal processes in the plant. Freshly fallen 

 rain may have sufficient radioactivity to retard 

 growth of plant organs. The same may be 

 true of tap-water previously exposed to the 

 emanations of radium. 



Alcoholic fermentation, and respiration, 

 both aerobic and anaerobic, were found to re- 

 spond to stimulus. On the other hand, 

 tropistic responses were not with certainty 

 demonstrated. 



The profound influence of the rays of ra- 

 dium is manifest if we look at the abnormali- 

 ties arising in the cells and tissues of plants 

 exposed. Thus in the hypocotyls of beans, 

 lupins, etc., retardation of growth was accom- 

 panied by a lack of coordination in histogen- 

 esis, stoppage of cell-division, acceleration of 

 tissue-differentiation, decrease in size of the 

 cells. In a given case any one or all of those 

 effects may be found. Mitosis in any of its 

 phases is likely to be profoundly modified with 

 marked distortion of the mitotic figures and 

 disturbance of the normal processes of nuclear 

 division. 



The attempts to induce mutation by radio- 

 activity were not continued to success, though 

 some intimations were obtained that it may 

 be possible to do so. 



The paper closes with an extended theoret- 

 ical discussion of about seventeen pages. 



From the facts included in this descriptive 

 review it is evident that this work has a com- 



