REVIEWS 521 



experiments on " muscle and nerve " is proceeding too rapidly ; time and experience 

 in practical classes will be required for the selection and teaching of experiments 

 upon man. There is evidence of this in the present work, for if allowance be made 

 for the demonstrations upon anaesthetised mammals which must be performed by a 

 teacher who holds a licence to make experiments upon animals, there does not 

 appear to be sufficient practical work to occupy the student during two terms, the 

 time generally given to experimental physiology. The teaching of practical physio- 

 logy for medical students is more thorough in this than in any other country, and 

 it would be a step backwards if the course were shortened. It is probable that 

 the authors will find it necessary to extend the exercises. 



Another suggestion which one would wish to make for future editions of the 

 book is that typical graphic records should be included ; in the present edition the 

 student will miss the guidance afforded by such tracings, and an extra tax will be 

 thrown upon the teacher. In many exercises a more detailed description of the 

 results to be expected would be an advantage. 



The book is a useful addition to the practical works upon experimental physio- 

 logy and will be welcomed by all teachers of medical students. 



M. S. Pembrey. 



Researches on Fungi. An Account of the Production, Liberation and Dispersion 

 of the Spores of Hymenomycetes treated Botanically and Physically, also 

 some Observations upon the Discharge and Dispersion of the Spores 

 of Ascomycetes and of Pilobolus. By A. H. Reginald Buller, B.Sc. 

 (Lond.), D.Sc. (Birm.), PH.D. (Leip.)., Professor of Botany at the Uni- 

 versity of Manitoba. [Pp. xi-i-287-l-Pl. V + figs. 81.] (London: Longmans, 

 Green & Co., 1909. Price 12s. 6(7.) 

 The massive fruit-bodies of the Hymenomycetes, such as those of Ag^aricus and 

 Polyporits, are clearly complicated structures with a very high degree of adaptation 

 to the production and discharge of spores. The detailed mechanism of these 

 reproductive organs, however, has been almost completely neglected, and until 

 lately botanists were ignorant of the way in which the spores separated from the 

 basidia and escaped from the pores or from between the gills, and little was known 

 of the number of spores produced or of how they were dispersed. 



As a result of numerous observations and ingenious experimentation Prof. 

 Buller has enabled us for the first time to form a clear picture of the hymenomycetous 

 fruit-body as a working mechanism. By a series of careful measurements and 

 calculations the author first gives body to the generally accepted view that the 

 development of gills, spores, spines, etc., is for the purpose of increasing the 

 spore-bearing surface. He shows that the common mushroom has 20 times 

 as much hymenial surface as it would have in the absence of gills ; in Polyporus 

 squamosiis the proportion is 11, and in a specimen oi Fames igniariiis with twenty 

 layers of tubes it is 1,000. The large area of the hymenium would lead us to 

 expect a lai-ge spore-production, but one is hardly prepared for the enormous 

 profusion in which these structures are produced. By collecting the spores and 

 distributing them in water and then counting the number in a small sample it 

 was shown that a single pileus of the ordinary field mushroom may produce 

 1,800,000,000, and Copn'/iiis cotnattis 1,000,000,000 ; the number of spores pro- 

 duced by a single Polyponcs sqinunosus with many pilei may exceed 50,000,000,000, 

 and that of a Giant Puff-ball may reach seven billion. 



The author was also able to show that the fall of spores from the fruit-body 

 could be easily observed with the naked eye by throwing a strong beam of light in 



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