i64 SCIENCE PROGRESS 



in the light of the author's own experiments. The book is divided into a series 

 of chapters each deaUng with some special phase of the movement, e.g. 

 Transformation of Endoplasm into Ectoplasm ; Experiments on the Surface 

 Layer ; Streaming, Contractibility, etc. In addition to this. Professor SchaefEer 

 also directs attention to a noteworthy fact, namely that the Amoeba in pro- 

 gression follows an orderly path representing a projection on a plane surface of 

 a helical spiral unless it is interfered with by external stimuli. This is de- 

 veloped further, and it is pointed out that it is related to the similar movement 

 of free-swimming organism like ciliates, flagellates, rotifers, worm larvae, etc., 

 and may even be reproduced in the higher animals, including man himself, if 

 the organs of orientation are not functioning. The similarity of the effects 

 of alteration of temperature upon those orderly paths in different animals 

 suggests that there is an underlying physical reason for this mode of progres- 

 sion. The book is well and thoughtfully written, and contains a useful 

 bibliography. C. H. O'D. 



Territory in Bird Life. By H. Eliot Howard. [Pp. xiii + 308, with 11 

 plates by G. E. Lodge and H. Gronvold, and 2 plans.] (London : 

 John Murray. Price 21s. net.) 



Mr. Howard's present book is an elaboration of his theory of bird territory 

 as outlined in his earlier celebrated work on the British Warblers. Mr. 

 Howard sets out to prove that the possession of territory is the dominating 

 impulse that accounts for most, if not all, of the actions of a male bird in 

 "the mating season, even the almost universal habit of migration being attri- 

 l)uted to this stimulus. The theory is an exceedingly interesting one, and 

 ;gains weight from the mass of careful observations that the author marshals 

 in its support. 



That birds appear actually to own and hold sole sway over certain tracts 

 of land during the breeding season, the centre of which is, during the main 

 part of the period at all events, their nest, is well known to all field workers. 

 That the owner resents the intrusion of other individuals of his own, and 

 frequently unrelated species, is equally well known. Mr. Howard demonstrates 

 that the selection of a territory is the first step towards mating and repro- 

 duction, and that that selection takes place before a mate is secured. Already 

 at that stage it is the cause of innumerable battles, and therefore these, 

 almost universally attributed to the influence of the female, are in reality 

 fights for the possession of land, and not a mate. In this connection the 

 author points out that, of most migratory species, the males are the first to 

 come, the females in some cases arriving at a much later date. Having 

 established this point, he dilates on the importance of the possession of a 

 definite territory in securing a mate. He points out that in this manner 

 the males are fairly equally distributed over their range, and the females, 

 when they do arrive, have no difficulty in finding a mate. Without the 

 territory and its consequent effect of equal distribution, the females might 

 have great difficulty in attaining this end. Thus time and energy are saved, 

 and early and successful reproduction for the majority is ensured. To the 

 importance of song as an advertising medium for the site of the males and 

 their stations, a chapter is devoted. The relation of different species to 

 each other, and the overlapping of their ranges, is treated at length in another 

 chapter. Finally, the possession of a territory is cited as the main induce- 

 ment for the northern migration in the spring — a truly startling conclusion. 



Though we may not accept Mr. Howard's views in their entirety, we 

 must congratulate him on a piece of work of exceptional interest. Through- 

 out he supports his statements with accurate observations, and from these 

 deduces his arguments with very sound logic. There is no doubt that the 

 work is an important addition to ornithological literature. 



