372 



THE POPULAR SCIENCE MONTHLY 



to introduce the student to the present state 

 of knowledge in botanical science. He not 

 only explains the phenoinena of plant-life 

 already accurately known, but also indicates 

 those theories and problems in which bo- 

 tanical research is at present engaged. Kef- 

 erences are given throughout the volume, 

 which direct the student to those writings 

 that contain fuller discussions of the points 

 in question, that he may be enabled to form 

 for himself an enlightened judgment. The 

 illustrations are mostly original, and many 

 of them the result of laborious investigation. 

 The work consists of three divisions : 

 General Morphology, Special Morphology, 

 and Physiology. Under General Morphol- 

 ogy, there are three chapters treating: 1. 

 Of the morphology of the cell ; 2. Morphol- 

 ogy of the tis.ues ; and 3. Morphology of 

 the external conformation of plants. Spe- 

 cial morphology deals with the groups of 

 plants as at present arranged in classes. 

 Physiology is treated in seven chapters : 



1. On the molecular forces in the plant; 



2. Chemical processes in the plant ; 3. Gen- 

 eral conditions of plant-life; 4. Mechanical 

 laws of growth ; 5. Periodic movements of 

 the n)ature parts of plants, and movements 

 dependent on irritation ; 6. The phenome- 

 non of sexual reproduction ; V. The origin 

 of species. 



The general reader, who is interested in 

 modern scientific discussion, will find this 

 an entertaining volume, because of its vital 

 relation to questions uppermost in modern 

 thought. For instance, the world-wide in- 

 terest in " protoplasm " aroused by Prof. 

 Huxley's address at Edinburgh, finds am- 

 ple satisfaction in the explanations of cell- 

 structure and cell-function. As bearing 

 upon this subject we quote the following, 

 which will be new to many readers:. 



"Under this head" {Myxomycetes) "is 

 included a numerous group of organisms 

 which, in many respects, differ widely from 

 all other vegetable structures, but, in the 

 mode of formation of their spores, stand 

 nearest to fungi, on which account we may 

 treat them as a supplement to that class. 

 The Myxomycetes are remarkable in no ordi- 

 nary degree from the fact that, during the 

 period of their vegetation and assimilation 

 of food, they do not form cells or tissues. 

 The protoplasm, which in all other plants is 

 also the general motive power of the phe- 



nomena of life, remains in them during the 

 whole of this period perfectly free, collecta 

 into considerable masses, and assumes va- 

 rious shapes from the internal ibrce residing 

 in it without becoming divided into small 

 portions, which surround themselves with 

 cell-walls (or become cells). It is only when 

 the protoplasm jiasses into a state of rest in 

 consequence of being surrounded by unfa- 

 vorable conditions, or when it concludes its 

 period of vegetation by tlie formation of the 

 reproductive organs its internal and exter- 

 nal movements ceasing at the same time 

 that it breaks up into small portiors which 

 surround themselves with cell-walls, and 

 which even then never form a tissue in the 

 proper sense of the term." 



The book is penetrated throughout with 

 modern views in biology, and also illustrates 

 the truth of the remark that, while other 

 nations are disputing about the doctrines 

 of Darwin, the Germans accept them, and 

 are working on the new basis afforded by 

 them. In the chapter on the '' Origin of 

 Species," full of the fruitage of this new 

 line of study, we find the following: 



" The scientific basis for the theory of 

 descent rests in the fact that it alone is able 

 to explain in a simple manner all the mutual 

 relationships of plants to one another, to 

 the animal kingdom, and to the facts of ge- 

 ology and paleontology, their distribution 

 at different times over the surface of the 

 earth, etc. ; since it requires no other hy- 

 pothesis than descent with variation, and the 

 continued struggle for existence which per- 

 mits those forms only to persist that are en- 

 dowed with sufBeiently useful properties, 

 the others perishing sooner or later. But 

 both these hypotheses are supported by an 

 infinite number of facts. The theory of de- 

 scent involves only one hypothesis that is 

 not directly demonstrated by facts, namely, 

 that the amount of variation may increase to 

 any given extent in a sufficiently long time. 

 But, since the theory which involves tliis hy- 

 pothesis is sufficient to explain the facts of 

 morphology and adaptation, and since these 

 are explained by no other scientific theory, we 

 are justified in making this assumption." 



Sixth Annual Report of the State Board 

 OF Health of Massachusetts. 379 

 pages. January, 1875. 



This report opens with a feeling tribute 

 of respect, from the pen of Dr. Henry I. 

 Bowditch, Chairman of the Massachusetts 

 State Board of Health, to the memory of 



