122 THE JOURNAL OF BOTANY 



Mr. C. 0. Rosendahl publishes the results of his Observations 

 on Plant Distribution in Renfrew District of Vancouver Island, his 

 object being to set forth a few main facts bearing upon plant 

 ecology and plant floristics without unnecessary details. He treats 

 his subject under the following main headings : — (1) Marine forma- 

 tions ; (2) Formations of the beach ; (3) Formations of the forest- 

 country ; and these are further subdivided. He then gives an enu- 

 meration of the plants collected, and points out that the chief mass 

 of the island vegetation is composed of gymnosperms ; that the 

 monocotyledons are more numerous than the dicotyledons; and 

 that the ferns are profuse in number, but poor in species. 



It is, we suppose, to show off the half-tones of the plates that 

 the paper is so heavily mineralized. The volume is the heaviest 

 one for its size that we have ever held in our hands. 



A. & E. S. G. 



Die Selbsterhitzung des Hens ; eine biologische Studie. Von Dr. Hugo 



Miehe. 8vo, pp. 126. Jena : Fischer. 1907. 



When scientific research is directed to the elucidation of long- 

 familiar phenomena, the interest aroused is prompt and keen, espe- 

 cially if the explanation offered meets all the facts of the case. The 

 heating of hay or corn too hastily garnered, which may even result 

 in spontaneous combustion, is one of these natural happenings well 

 known to all who are interested in agriculture. It has been de- 

 monstrated to be due to bacterial action, and Dr. Hugo Miehe, of 

 Leipzig, has published an elaborate treatise, setting forth the 

 results of his many experiments on the subject. 



He records first of all the different cases in which such physio- 

 logical heating occurs : in grasses, where a moderate amount of 

 heat is encouraged and utilized in the formation of ensilage; in 

 tobacco-leaves, where it is a factor in the ripening process ; and in 

 hotbeds of manure, which are valuable to the gardener. Hops, 

 on the contrary, are spoiled by heating, and careful drying is essen- 

 tial. The conditions required to induce heating are a sufficient 

 moistness, and a large enough quantity of the material to ensure 

 tight packing and the consequent absence of ventilation. Miehe 

 secured these condition with a quantity of freshly cut hay, and his 

 first experiments were directed to gauging the rise of temperature 

 in different parts of the mass ; the detailed results are given in 

 tabular form. On the second day the hay begun to " steam " and 

 take on the characteristic odour of decaying fruits. In six days the 

 highest temperature, 68-5° centigrade, was reached at the centre of 

 the mass. 



Evolution of heat is often due to chemical changes, but Miehe, 

 by a further series of experiments, proved that heating in hay was 

 due solely to biological action. He sterilized his material and go fc 

 no change in temperature ; the same hay was then sprinkled with 

 water in which hay and earth had been soaked, and self-heating 

 quickly followed. All the experiments pointed to the connection 

 of some living organisms with the heating process. Further exanii- 



