516 REVIEWS^ — THE GENETIC CYCLE IN ORGANIC NATURE, 



obscurity of the questions involved ought to be the interest excited 

 in attempts at their solution. It may safely be said that candid 

 inquirers will find in Dr. Ogilvie an useful guide, and whatever may 

 be thought of some of his theoretical views, the information brought 

 together is such as could only be collected by the study of many 

 volumes relating to different departments, and some of them difficult 

 of access, whilst the systematic manner in which it is presented 

 greatly enhances its value. In order to give some idea of the work 

 before us we shall first lay before our readers the character and order 

 of the subjects treated, in a list of the titles of the several chapters. 

 "We may then select a few particulars for more special notice, without, 

 however, attempting to examine in detail the peculiar views proposed, 

 or to give any opinion respecting them, beyond our conviction that 

 the book deserves the attention of all who pursue physiological 

 studies. The divisions of the subject are as follows : — I. Derivation 

 of Organic Beings. II. Survey of the Reproductive Process in 

 the Vegetable Kingdom. III. Do. in the Animal Kingdom. IV. 

 Nature and Varieties of Alternation of Generations. V. Pullulation. 

 VI. Embryogeny, as representing one Form of Alternation. VII. 

 Representation of the other Forms. VIII. Relations of Ova and Gemmae. 

 IX. Summary of Conclusions. X. Cases Simulating Alternation of 

 Generations. XI. Homological Relations of the Structures concerned 

 in the Genetic Cycle. There is an appendix of tables exhibiting the 

 order and supposed relations of phenomena in different divisions of 

 organized beings, and there are six illustrative plates, which, though 

 of no great merit in their execution, sufficiently convey the ideas 

 intended, and will be found an assistance by such readers especially 

 as are little familiar with the subjects. The author commences by 

 laying down as the best distinction between organized and inorganic 

 substances the derivation of the former " by a process more or less 

 direct from previously existing individuals of a like kind." In the 

 case of organic bodies, which is thus contrasted with the nearest 

 approaching results of mechanical or chemical agencies, "not only 

 must their ultimate chemical elements be present in some shape or 

 other, but they must be present as combined by the prior operation of 

 the living powers of individuals of a like kind into fertilized germs or 

 other reproductive bodies. If such a germ or reproductive body has 

 been normally constituted, then, and then only, will the application 

 of certain appropriate influences of light heat, chemical action, &c., 



