36 Bristol. — On the Alga- Flora of some Desiccated 
looked, and, in this country at any rate, no systematic work has so far been 
done in connexion with them. This is all the more extraordinary since the 
researches of Kossowitsch, Bouilhac, Giustiniani, Schloesing, Laurent, and 
others clearly indicate that there is an intimate connexion in the soil 
between algae and the nitrogen-fixing bacteria, and that algae probably 
play quite a prominent part in the activities carried on by these organisms. 
In 1910 Esmarch 1 published a paper on the blue-green algae of the 
soils of the German African colonies, and as a result of his experiments he 
concluded that cultivated soils are throughout richer in blue-green algae 
than are uncultivated soils, and that in cultivated soils algae occur not only- 
in the surface but also in the lower layers. As a consequence of this work 
he further undertook an investigation of the distribution of the blue-green 
algae in different soils of Schleswig-Holstein 2 for the purpose of finding 
out not only what species are present in different kinds of soil, but also the 
depths to which they may be found and the possible reasons for their 
occurrence in such positions. 
Meanwhile, in 1913, Robbins 3 published a paper on the algae in 
some Colorado soils, in which he described twenty-one different species 
obtained from cultures of twenty-two different soils, and discussed their 
probable connexion with the accumulation of unprecedented quantities of 
nitrates in certain soils in Colorado. 
Petersen’s work 4 on the sub-aerial algae of Denmark is a valuable 
contribution to our knowledge of soil-algae, especially in so far as it 
concerns soil-diatoms ; but his investigations of the green algae appear to 
have been confined to forms visible on collection to the naked eye, and his 
lists can therefore scarcely be regarded as exhaustive in this direction. His 
omission of all reference to blue-green algae also makes it difficult to realize 
a true conception of the nature and extent of the algal flora of the soils. 
In the course of an investigation of soil-protozoa, Dr. T. Goodey and 
Dr. H. B. Hutchinson recently obtained certain algal forms from old stored 
soils and sent them to Professor G. S. West for identification. This was 
impossible at first, but after an investigation extending over several months 
Professor West was enabled to^tate that spores of Nodidaria Harveyana , 
(Thwaites) Thuret, are able to retain their vitality for a period of sixty-six 
years. 5 This discovery led him to suggest that the study of a number of 
dried soils by means of cultures might be a profitable one in ascertaining 
1 Esmarch, F. : Beitrag zur Cyanophyceen -Flora unserer Kolonien. Jahrbuch der Ham- 
burgischen wissensch. Anstalten, xxviii, 3. Beiheft, S. 62-82, 1910. 
2 Esmarch, F. : Untersuchungen iiber die Verbreitung der Cyanophyceen auf und in ver- 
schiedenen Boden. Hedwigia, Band lv, Heft 4-5, September 1914. 
3 Robbins, W. W. : Algae in some Colorado Soils. Bulletin 184, Agr. Exp. Sta. Colorado, 
June, 1912. 
4 Petersen, J. B. : Danske aerofile alger. D. Kgl. Danske Vidensk. Selsk. Skrifter, 7 Rmkke, 
Naturv. og Mathem., Afd. xii, 7, 1915. 
5 Vide West, G. S. : Algae. 1 Camb. Bot. Handbooks, p. 28, 1916. 
