224 



SCIENCE 



[N. S. Vol. XXV. No. 632 



presented in attractive form and for the be- 

 ginner is one of the best books of its kind 

 with -which I am acquainted. 



A. E. Crook 



Natubal History Museum, 

 Spbingfield, Illinois 



SCIENTIFIC JOURNALS AND ARTICLES 

 The Journal of Experimental Zoology, 

 Volume III., No. 4 (December, 1906), con- 

 tains the following papers : ' The Physiology 

 of Regeneration,' by T. H. Morgan. Ex- 

 periments on salamanders, earthworms and 

 fish show that the rate of regeneration 

 in a posterior direction is more rapid the 

 further the cut surface from the original end. 

 In other words, the more of the old part re- 

 moved, the more rapid the new part regener- 

 ates. Other experiments show that this is not 

 due to food conditions, but that the rate de- 

 pends on a formative factor. It is suggested 

 that it is the relation of tension in the old and 

 the new part that is a controlling factor in 

 regeneration and growth. ' Hydranth Forma- 

 tion and Polarity in Tubularia,' by T. H. 

 Morgan. Experiments on tubularia show that 

 the polarity is an expression of the direc- 

 tion of the gradation of the differentiated 

 materials. The greater the differentiation 

 in one direction the longer the road that 

 must be traveled to produce a different kind 

 of structure. The gradation acts as a physical 

 factor in development, determining the ten- 

 sion relations in the old and new part. 

 ' Studies on the Development of the Star- 

 fish Egg,' by D. H. Tennent and M. J. 

 Hogue. This paper describes the partheno- 

 genetic development of the star-fish egg fol- 

 lowing treatment with CO,, the phenomena 

 occurring as a result of first treating the egg 

 with COj and later fertilizing it, and the 

 results of subjecting fertilized eggs to the 

 influence of CO,. ' Some Experiments on 

 the Developing Ear Vesicle of the Tadpole 

 with Relation to Equilibration,' by Geo. L. 

 Streeter. A study of the normal develop- 

 ment of the function of equilibration in the 

 tadpole, and the variations produced by re- 

 moval and transplantation of the ear vesicle 

 during the early larval period. ' The 



Relation between Eunctional RegTilation and 

 Form Regulation,' by C. M. Child. The 

 organism is to be regarded as primarily a 

 dynamic or functional complex, and structure 

 and form are visible expressions of dynamic 

 conditions : consequently the regulation of 

 form and structure is fundamentally a dynam- 

 ic or functional regulation and only as such 

 can its phenomena be satisfactorily inter- 

 preted. ' Study of the Spermatogenesis of 

 Coptoeycla Aurichalcea and Coptocycla Gut- 

 tata, with especial reference to the Problem 

 of Sex Determination,' by W. N. ISTowlin. An 

 investigation of two species of beetles re- 

 vealed the presence of an unequal pair of 

 chromosomes, the so-called ' idiochromosomes ' 

 of Wilson, which, we have strong evidence for 

 believing, transmit or determine the character 

 of sex. The small one invariably occurs in 

 the male somatic cells and represents the re- 

 cessive form of the female character; the 

 large one in the female somatic cells and bears 

 the male character. ' Torsion and Other 

 Transitional Phenomena in the Regeneration 

 of the Cheliped of the Lobster {Homarus 

 Americanus) ,' by Victor E. Emmel. A 

 comparison of the regenerative with the 

 ontogenetic method of development. ' The 

 Influences of Gases and Temperature on 

 the Cardiac and Respiratory Movements in 

 the Grasshopper,' by Eulalia V. Walling. The 

 influences of gases and temperature on the 

 respiratory and cardiac activities were found 

 to be practically the same on segments of the 

 isolated heart and isolated respiratory centers 

 as in the normal grasshopper. Moreover, it 

 was found that these activities may continue 

 in such specimens as long as four days in an 

 atmosphere of pure hydrogen. 



DISCUSSION AND CORRESPONDENCE 



Norton's elemjsnts of geology 

 The review of Norton's ' Elements of Geol- 

 ogy,' which appears in a recent number of 

 Science, Vol. 24, p. 590, prompts one to re- 

 peat the suggestion recently made, that the 

 legitimate function of a review in such a 

 periodical as Science is to give to the reader 

 an accurate impression of the general char- 

 acter of the work, both as to the ground which 



