'■U 



NA TURE 



[July 12, 1906 



nesota, in common with other States of the Middle 

 West, is year by year producing an army of workers 

 who have learnt to base their work on scientific 

 principles and to look to the results of scientific re- 

 search for the future development of their industry. 



The success of the American agricultural . colleges 

 in turning out trained craftsmen (they are not, per- 

 haps, equally successful in producing highty-trained 

 scientific experts) is to be traced to the intimate asso- 

 ciation of the practical and the scientific teaching. 

 On the one hand science is taught, but the mind of 

 the student is constantly being directed to its in- 

 dustrial applications ; on the other hand the industry 

 is taught, but with constant reference to underlying 

 scientific principles. Prof. Snyder's book is a capita) 

 example of the method of industrial teaching. It is 

 a text-book of dairying, but there is no rule-of- 

 thumb ; an appeal is made to reason ; processes are 

 advocated because found by experiment to be sound ; 

 the impression left on the student's mind is, " This 

 is the best to-day; there may be a better to-morrow." 



To take from the book two examples of the effect 

 of this method of training on industrial develop- 

 ment : — The advantages of the cold curing of Cheddar 

 cheese were established by Babcock and Russell at 

 the Wisconsin Experiment Station. It is a rational 

 process based on recent investigations on the action 

 of the natural enzymes in milk. The results were 

 only published in 1901, but already cold-curing fac- 

 tories have risen throughout Ontario and the cheese- 

 producing States of the Union, showing a readiness to 

 accept the results of scientific investigation, although 

 involving a large capital outlay, to which it is diffi- 

 cult to find a parallel in British agriculture. As the 

 second illustration, take the percentage of fat and total 

 solids in milk, 35 and 12 respectively, enforced as 

 the legal standard in Minnesota. To obtain such 

 milk, cattle must be bred up to this high standard. 

 The agricultural community is far-sighted enough 

 to see that, although it may involve hardship on 

 individuals, the high standard is an ad\antage to a 

 State where butter and cheese production is an im- 

 portant industry. 



The book should prove almost as useful to dairy- 

 men in this country as in America. There are few 

 ."Vmericanisms either in spelling or phraseology, and 

 throughout there is an insistence on the importance 

 of proper hygienic conditions in dairying, with several 

 useful suggestions as to how cleanliness can be 

 secured, which should be invaluable, for it is on account 

 of the neglect of such conditions in this country that 

 dairymen's troubles are generally due. The method of 

 calculating dividends in dairying is also worthy of 

 particular attention here. There are, unfortunately, 

 a few misprints and inaccuracies, together with curious 

 repetitions of the same statements, suggesting that the 

 book has been edited from lecture notes compiled in 

 card-catalogue form. As usual in American works, 

 the whole of the nitrogen compounds in foods are con- 

 sidered as proteids. The bibliography containing re- 

 ferences to American, German, and British scientific 

 papers is an excellent feature. T. S. D. 



NO. 191 5, VOL. 74] 



OVU BOOK SHELF. 



Gedanken iiber Vererbung. Dr. Alexander Petrunke- 

 witsch. Pp. 83. (Freiburg, i. B. : Speyer and 

 Kaerner, 1904.) Price 1.80 marks. 



The author thinks that clearness is gained if we regard 

 the organism as a continually changing mechanical 

 system with a life-cycle extending from the arbitrarily 

 chosen moment of oogenesis to the post-mortem death 

 of the last scrap of decaying tissue. An acquired 

 character is the result of a reaction of the system to 

 external influences, and presupposes a definite herit- 

 able structure capable of reacting, so that there is 

 no sharp boundary between acquired and inherited 

 characters. What is called a heritable character may 

 be due to a coincidence of successive reactions. The 

 concept of heredity strictly applies only to the germ- 

 cells; it is simply "the process which leads to the 

 formation of germ-cells whose structure is the same 

 as or like the parental germ-cells." Development is 

 the expression of this structure, and the formative 

 causes of development lie in the relation between the 

 system and its environment. An animate system can 

 only exist in definite conditions, which can only 

 oscillate within definite limits. Life is an adjust- 

 ment between the amplitudes of variation in the 

 animate system and in the environment, and involves 

 a progressive limitation of the organismal variability. 

 Those variations the causes of which lie in the os- 

 cillations of the germ-cell structure may be called 

 gametogenous or endogenous as contrasted with ex- 

 ogenous variations (modifications) which are acquired 

 in the course of life. This distinction will hold even 

 if we abandon the theory of the continuity of 

 the germ-plasm, and simply suppose that the germ- 

 cells are those cells which through chemical reactions 

 have attained the same structure as the parental germ- 

 cells. When this sameness is not attained variations 

 result, the amplitude of which may be trivial or fatal, 

 or it may be that a new pattern of system results 

 which we call a mutation. So far as we can see, the 

 author simplv re-states familiar facts and ideas in 

 a slightly novel way, and we do not share his con- 

 fidence that clearness is gained bv so doing. 



J. A. T. 



Giordano Bruno. In Memoriam of the ijth February, 

 1600. By Alois Riehl. Translated by ."Xgnes Fry. 

 Pp. 112. (Edinburgh and London : T. N. Foulis, 

 1905.) Price 2s. 6d. net. 



The life of Giordano Bruno is not altogether un- 

 familiar to readers of reviews in Nature. A larger 

 volume on this subject was reviewed about two years 

 ago (March 31, 1904, vol. Ixix., p. 505). Still earlier, 

 in May, 1900, the original of the present translation 

 was reviewed, and the reviewer expressed the wish 

 that Prof. Alois Riehl's essay could be presented in 

 English. This suggestion has led to the appearance 

 of the present volume. 



The first account of Giordano Bruno coming from 

 the pen of Prof. .Alois Riehl dates from 1889, the 

 year in which the present monument was erected 

 to Bruno on the site of his martyrdom. The ter- 

 centenary of Bruno's death on February 17, 1900, 

 formed the occasion for a second edition, in which 

 the account of Bruno's philosophy was revised. With- 

 out entering into minute detail, the present trans- 

 lation bears the impress of being a good one, and 

 when the small size of the book is taken into account 

 the description of Bruno's life will be found to be 

 as full and complete as could be possibly expected. 



