160 SCIENCE PROGRESS 



Now that it is clear that Para rubber is the best variety to grow in Trinidad, 

 this planting industry can be extended on a proper basis, and its development 

 will make for stability in agricultural conditions in this important island. The 

 exploitation of the tropics will soon be renewed with increased vigour, and the 

 publication of this report shows that Trinidad is alive to the great possibilities of 

 tropical agriculture under scientific direction. 



F. T. Brooks. 



Soil Biology: Laboratory Manual. By A. L. Whiting, Ph.D. [Pp. x + 143.] 

 (London : Chapman & Hall ; New York : John Wiley & Sons. Price 6s. 

 net.) 



This book, as indicated in the sub-title, is essentially a laboratory handbook, and 

 by far the greater part is devoted to the description of experiments, or " practices " 

 as they are here termed, to be carried out by the student. Of these there are 

 thirty-three in all, of which number most deal with soil bacteria and their pro- 

 ducts ; two are concerned with the soil fungi ; one with alga? ; and one with 

 protozoa. The directions for carrying out each experiment are followed, in every 

 case, by a few references to appropriate literature and several questions. 



In the second part, which comprises about one-third of the whole, the methods 

 employed in soil biology are described. These include tabulated formulae and 

 general information respecting culture media, stains for bacteria, quantitative and 

 qualitative determination of nitrogen compounds and other substances, methods 

 of pot culture, etc. 



There is a very full table of contents which in a great measure atones for the 

 absence of an index. The manual is well suited for students already acquainted 

 with bacteriological and chemical methods, but is not intended for those who 

 have not such preliminary training. Even, however, at the risk of the volume 

 being less handy for laboratory use, rather more detailed directions might 

 perhaps have been given so as to have rendered the admirably conceived 

 exercises available to a wider range of students. 



E. J. Salisbury. 



The Dissemination of Parasitic Fungi and International Legislation. By 



E. J. Butler, M.B., F.L.S. Memoirs of the Department of Agriculture 

 in India. Vol. IX., No. 1. [Pp. 73.] (Calcutta: Thacker, Spink & Co. 

 Price 2s. net.) 



Mr. Butler, after emphasising the importance of dissemination by means of the 

 mycelium carried in the living plant tissue in certain cases {e.g. Potato Blight), 

 deals with the more frequent mode of dispersal by means of spores. These latter 

 are produced in prodigious numbers by many fungi and, by their capacity for 

 withstanding desiccation and their small size, are eminently suited for conveyance 

 by air currents or carriage by animal agency. These means of dispersal are 

 probably the only ones effective over long distances, although other agents come 

 into play within a short distance of the source of infection. 



It is chiefly with the long-distance spread that Mr. Butler is concerned. 

 Evidence, mainly circumstantial, is advanced to support the view that fungal 

 spores are seldom carried long distances (more than about 50 miles perhaps) by 

 wind agency. 



Thus, the chestnut-free belt of the Catskill Mountains appears to offer an 

 impassable barrier to the chestnut-bark disease ; the known history of the spread 



