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SCIENCE 



[N. S. Vol. XXXI. No. 'li 



synthesis rather than those of splitting and 

 oxidation. Hypertrophy as an outcome of 

 increased functional activity is a familiar 

 phenomenon, but as Nussbaum remarks the 

 hypertrophy induced by testicular or ovar- 

 ian hormones resembles rather the effect 

 of the growth energy exhibited by the de- 

 veloping embryo, in that it is dependent 

 upon influences other than those arising 

 from functional use. What these influ- 

 ences may be is at present a matter of pure 

 speculation. In his recent most interesting 

 contributions to our knowledge of growth 

 Rubner has been led to assume that the 

 property of growth in the young organism 

 is connected with certain special chemical 

 complexes in the protoplasmic material, 

 complexes which have nothing directly to 

 do with the simple maintenance of the nu- 

 trition of the cell and which after adult 

 life is reached disappear for the most part 

 from the general soma. In line with this 

 hypothesis one might assume that the hor- 

 mones given to the blood by the reproduc- 

 tive cells contain such complexes which 

 when anchored in certain tissues lead to an 

 accelerated growth. Perhaps the clearest 

 and most interesting experiments made 

 upon the reproductive hormones are those 

 reported by Nussbaum. He chose for his 

 experiments the males of Rama fusca 

 whose reproductive organs go through a 

 cyclical development each year. At the 

 proper period the preparation for the 

 mating season shows itself in the hyper- 

 trophy of the seminal vesicles, of the 

 thumb pads and of certain muscles in the 

 forearm. If the frog is castrated these 

 hypertrophies do not occur, or if they have 

 begun before the castration is performed 

 retrogressive changes take place. On the 

 other hand, the usual hypertrophy of the 

 nuptial organs can be initiated in a cas- 

 trated frog if pieces of the testis from 

 another frog are introduced into the dorsal 



lymph sacs. The pieces thus introduced do 

 not become grafted permanently but are 

 gradually absorbed and the growth of the 

 thumb pads and of the muscles in the fore- 

 arms falls off after this absorption is com- 

 pleted. Nussbaum believes that the stim- 

 ulating effect of the testicular hormones 

 is not exerted directly upon the tissues 

 which show the increased growth, but 

 rather upon the portions of the central 

 nervous system which innervate these 

 tissues. This belief rests upon the experi- 

 mental fact that if the peripheral nerves 

 going to the glands and papillse of the 

 thumb pads are severed on one side the 

 testicular hormone affects only the other 

 intact side. This experiment and the con- 

 clusion drawn from it opens up the inter- 

 esting question whether perhaps the repro- 

 ductive hormones in general exert their 

 effect through the central nervous system. 

 This has not been the usual belief, and the 

 experiments of Nussbaum are open to the 

 obvious objection that the section of the 

 peripheral nerves may have induced cer- 

 tain secondary changes in metabolism 

 which indirectly antagonized the action of 

 the testicular hormone. At present these 

 experiments, so far as I know, have not 

 been repeated with this objection in mind 

 and it is somewhat gratuitous to criticize 

 the author's conclusions until further work 

 is reported. 



William H. Howell 

 The Johns Hopkins Uni-versity 



'SIR WILLIAM CROOKES^ 

 The generation just passing away and that 

 now enjoying the vigor of its beginning, are 

 fortunate in this country, because they are- 

 recognizing the privileges and advantages of 

 anniversary celebrations. The indulgence in 

 ^ Address of Professor Charles Baskerville before 

 the Chemists' Club, Harvard Night, November 27, 

 1909, on which occasion Sir William Crookes was 

 elected to honorary membership in the club. 



