382 NOTES AND COMMENTS [December 



Those who are seriously interested in the question would find 

 food for reflection if they would take opportunity to become 

 acquainted with " Nature Studies in Berkshire," by John Coleman 

 Adams (New York and London : G. P. Putnam's Sons, pp. 225, 1899). 

 It is not that there is any new discovery in the book ; it is the redis- 

 covery of delight. It will probably not even instruct, but it may 

 possibly enlighten. It is not an educational compendium ; it is a 

 work of art. In a beautifully bound and printed volume, with fine 

 photogravures, and in a style which sometimes reminds one of 

 Burroughs, the author tells us of the American Berkshire ; and the 

 titles of some of the chapters will suggest his happy mood : A Whisper 

 from the Pines, The Seamy Side of Summer, At the Sign of the 

 Beautiful Star, The Great Cloud Drive, The Fruitage of Beauty. He 

 excels himself perhaps in " The Circumvention of Greylock," which 

 means " a bicycle run round a hill," but the difference between his title 

 and ours is the difference between light and darkness. We have re- 

 ferred to the book here because of our conviction that its value lies in 

 its being an expression of delight in nature by a cultured gentleman, 

 and that if " nature study " does not at least lead towards this, it is not 

 likely to mean more than another millstone about the neck of youth. 



The Production of Parthenogenesis in a Sea- 

 Urchin. 



It is not long since Delage made a remarkable experiment, which 

 seemed to prove that the nucleus and centrosome of the ovum were 

 not essential to reproduction. Now comes Professor Loeb of Chicago, 

 and, likewise by actual experiment, makes out that even the spermato- 

 zoon is not necessary. His results are given in a short note " On 

 the nature of the process of fertilisation and the artificial production 

 of normal larvae (plutei) from the unfertilised eggs of the sea-urchin " 

 (Amer. Journ. Physiol, vol. iii. pp. 135-138, Oct. 1899). As the 

 outcome of a long series of experiments and inductions, he was led to 

 believe that the only reason why the eggs of marine animals did not 

 develop parthenogenetically was that something in the constitution of 

 sea- water prevented it. That something, he inferred from experi- 

 ments on the contraction of muscles, was the presence or absence of 

 ions of sodium, calcium, potassium, and magnesium. The two former 

 require to be reduced, the two latter to be increased : " a great number 

 of variations in this sense might bring about the desired effect." 

 Without going into details, Professor Loeb states briefly that " the 



mixture of about 50 per cent —-n MgCl 2 with about 50 per cent of 



