55 6 SCIENCE PROGRESS 



somatic tissues, but the influence exerted on all somatic tissues which can be 

 affected by such changes as may be induced by variation in the food supplied to 

 the parent body. Such influence may be transmitted either directly through the 

 blood, or indirectly by means of the secretions of various organs {e.g. ductless 

 glands), and may exert very profound influence on the growing germ-plasm. 

 The internal secretion of the generative gland itself may be affected by this means. 



Is it not eminently possible that the increased power of variation with which 

 cultivated plants are credited maybe derived from such a source ? Their capacity 

 for wide variation is associated with a great change in the nutriment provided to 

 them by special cultivation of the soil, and may well be largely determined by 

 that means. 



To what extent changes in the quality of nutrition conveyed to the germ-cell 

 may affect the growing plasm, it is not possible to say in the present state of our 

 knowledge ; but if the effect should be that the development of certain inherent 

 qualities is stimulated while that of others is destroyed, the normal balance of 

 power will thus be definitely changed, and, if so, will be inherited in that changed 

 condition. 



Mr. Elliot claims that "a physiological somatic modification can only be 

 caused by a factor which operates for an appreciable proportion of the life of the 

 soma." And on that ground he bases his contention that " the germ-cell which 

 has existed from the most extreme antiquity " must remain under any modifying 

 influence for a proportionately lengthened period in order that it shall be 

 affected at all. 



But in view of the results obtained by many experimental embryologists it is 

 hardly possible to accept Mr. Elliot's claim ; indeed, it does not necessarily appear 

 to be a fact which can be so stated. Moreover, if the germ-cell has existed from 

 the most extreme antiquity, that is no proof that the germ-plasm is incapable of 

 modification ; it is begging the whole question to assume this. Whether a drastic 

 alteration in the relative value of the inherent qualities of germ-plasm requires 

 many generations or not, does not concern us ; if it takes place at all, then 

 Lamarck's theory is not yet " entering upon the final stage of oblivion," as his 

 translator is disposed to believe. 



It is perhaps permissible to urge, here, that, in dealing with unknown quantities 

 of such extreme delicacy it is premature to assert dogmatically what is and what 

 is not possible in regard to them. Anatomically the germ-cell is not isolated from 

 the somatic cells, the germ-plasm and soma-plasm are in continuity — indeed, it is 

 impossible to say where the one ends and the other begins. Physiologically, 

 therefore, it is impossible to doubt that changes in the constitution of the soma- 

 plasm are communicable to the germ-plasm. To what extent, however, it is 

 necessary for the constitution of the soma-plasm to change in order that it may 

 affect the germ-plasm to an extent which is sufficient to modify its hereditable 

 qualities, is another matter, which still awaits definite proof. 



We incline to believe therefore that Lamarck's theory is not yet dead : that 

 it may still " succeed in giving rise to " ideas which may " set us on the way to 

 reach unknown truths." WALTER Heape. 



Zoological Philosophy. By J. B. Lamarck. Translated with an Introduction 



by Hugh Elliot. [Pp. xcii + 410.] (London, 1914 : Macmillan & Co., 



Ltd. Price 155-. net.) 



For many years the inheritance of acquired characters was one of the most 



eagerly discussed questions, and then, largely through the influence of Weismann 



