NATURE 



6i 



THURSDAY, MARCH i8, 1909. 



KEVJ LIGHTS ON. PROTOPLASM IN 



PLANTS. 



(i) Ei>ilcitung in die experimentelle Morphologic der 



Pflanzen. By Dr. K. Goebel. Pp. viii+260. 



(Leipzig and Berlin : B. G. Teubner, 1908.) Price 



8 marks. 

 (2) Parthenogenesis iind Apogamie im Pflansenreiche. 



By Dr. Hans Winliler. Pp. 166. (Jena : Gustav 



Fischer, 1908.) Price 4.50 marks, 

 (l) '"pHE study of botany has passed through many 

 -I- different phases, but it has tended more or 

 less steadily towards the fuller recognition of plants 

 as living beings, to be studied in the whole cycle from 

 their beginnings through their maturity to their decay, 

 including their provision for the continuance of the 

 race despite the death of the individual. For a time 

 the motive for the study of plants was naturally the 

 desire to find out the uses to which they could be 

 put, and the keenest students were usually the 

 physicians in their search for useful drugs. After 

 the awakening of interest in such study for its own 

 sake, it passed necessarily through a period of de- 

 scription of forms previously unknown, followed by 

 efforts to bring order into the knowledge already accu- 

 mulated, and to discover some system by which the 

 various forms could be accurately identified. 



The invention of the microscope and of the methods 

 suitable for its employment as an instrument of re- 

 search opened up new fields to the student of living 

 things, but the living substance was not recognised 

 as the builder of the framework of cell-walls and 

 vessels until near the middle of last century. The 

 recognition of protoplasm as the " physical basis of 

 life " necessarily directed attention to the importance 

 of gaining a knowledge of its properties, of its re- 

 lations to its environment, and of its response to 

 stimuli. Improvements in the microscope and in the 

 technique of research, while helping to solve some 

 problems, have opened up new lines of inquiry, and 

 this has been peculiarly the case in recent years. 

 A considerable new literature has grown up dealing 

 with the questions that arise, and it is very desirable 

 to have the lines of inquiry and the results attained 

 presented in a clear and effective form, whether these 

 cover the whole field or relate to only a part of it. 

 The two works named above will be found most 

 useful guides, the first to the knowledge gained by 

 experimental researches into alterations in structure 

 induced by action of external stimuli, or environment, 

 and into regeneration when parts are injured or re- 

 moved, and the second to the production of new 

 individuals by the processes known as apogamy and 

 parthenogenesis, and the relation of these proc^ses 

 to the normal production of the embryo from the 

 fertilised ovum. 



Prof. Goebel speaks with the authority of an adept 

 on all questions of morphology; and in this new book 

 (based on a course of lectures delivered in the winter 

 of 1006, and issued as the first volume of a series of 

 handbooks on the methods useful in the study of the 

 NO. 2055, VOL. 80] 



natural sciences and of technology) there is presented 

 a most useful guide towards a clear view of what 

 has been accomplished, along with indications of 

 promising subjects of investigation. The division into 

 lectures has not been adhered to, the clearness of 

 exposition alone suggesting the work of a skilled 

 teacher; and, where desirable, the matter has been 

 treated with greater fulness than would have been 

 suitable in the original form. Numerous footnotes 

 refer the student to all important sources of informa- 

 tion. 



Vascular plants supply by far the greater part of 

 the material dealt with, mosses and thallophytes being 

 referred to now and again by way of comparison. 

 The necessity of studying the plant throughout its 

 development as a condition of understanding its true 

 nature and affinities is illustrated by examples that 

 show great diversity between the corresponding parts 

 of the young and of the adult, and the differences are 

 traced to causes the action of which can be tested by 

 experiment. The normal course of development is 

 analysed into periods, each with a distinctive char- 

 acter, these being successively morphological, during 

 which the members appear and cells are rapidly multi- 

 plied, and physiologico-biological, when the members 

 attain their full size and maturity, and fulfil their 

 part in the plant's well-being. Experiments prove 

 that the action of environment depends largely on the 

 period during which it has acted, and that the 

 characters of the earlier period may be retained in 

 the normally later stage, or may be reproduced in 

 that stage by the influence of an environment appro- 

 priate to the earlier. The Campanula rotiindifolia 

 ("harebell" of England, "blue-bell" of Scotland) is 

 found to be very well suited for these instructive ex- 

 periments, the forms of its leaves showing very quickly 

 the influence of changes in environment, and also 

 that similar results may follow apparently very dif- 

 ferent causes, such as diminished light, lessened 

 supply of water, or increase of the salts in solution 

 in the water. Prof. Goebel is led to the generalisa- 

 tion that these external influences act indirectly by 

 their altering the amount and kind of the food formed 

 by the plant, and required to permit of the normal 

 course of development, the external forms being con- 

 ditioned by the vital activities of the plants, and by 

 the food-supply to each part of it. Thus also he 

 accounts for the phenomena of regeneration where the 

 injury is not very great, or replacement by new 

 parts of a similar kind if the parts removed were 

 too extensive or too specialised in their structure to 

 be regenerated simply. The same generalisation is 

 used to explain the different behaviour of primary 

 and lateral axes and appendages, when uninjured, and 

 when lateral parts are modified to replace primary 

 members that have been destroyed. 



The quality of the food is held to explain the nature 

 of the parts 'formed. Thus stolons (as in Circaea) are 

 attributed to the amount of organised food, relatively 

 to the inorganic, or ash, supplied to the growing-point 

 of the stolon being greater than that supplied to the 

 leafy shoot. Potato tubers afford very favourable sub- 

 jects for experiments; e.g. if tubers are kept at not 



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