INTRODUCTION. xv 



Millenieters in diameter, can do more in its small laboratory than 

 our chemists with all the room and appointments that science 

 has suggested it builds its own cellulose walls from inorganic 

 matter. Chemists are hardly agreed upon the composition of 

 cellulose and the protein compounds, and if they were, they 

 could not introduce the life-principle to produce them." 



The polymorphism of Fresh-water Algse is not a new thought. 

 It has received varied attention during the past half of a century. 

 0. A. Agardh (Swede) in the earlier part of the present century 

 called attention to some peculiar observations made by himself. 

 The ideas were new and called forth severe criticism. Turpin 

 treated him severely as a false prophet. At the present day 

 some of his notions appear crude, but others stood the test of 

 later observations, and Agardh deserves commendation for the 

 direction he gave to later studies. Later (1840) followed Kuetzing 

 (Prussia) in high rank as an Algologist. He recognized a relation 

 between some of the lower unicellular forms with more fully 

 developed plants. 



Dr. H. Itzigsohn (Prussia, 1850) made a bolder stride in the. 

 study of the life-history of Hapalosiphon, and after two years 

 of close attention, jHiblished his observations in an exhaustive, 

 illustrated prodomus, bringing out many new facts relating to the 

 polymorphic character of this plant. Correctly and ably as his 

 work was done 1 it was not accepted but quietly ignored, appar- 

 ently for no other reason than that it struck too severe a blow at 

 the hitherto accepted theories of classification. At the same 

 time that Itzigsohn did so much to throw light on the life-history 

 of the Cyanophycea? (Schizosporese), I. B. Hicks did much in* 

 the study of some of the Chlorophycese. He called attention to 

 the work of Itzigsohn and to the contributions of Meyen, but 

 instead of awakening an interest of inquiry into the true character 

 of the unicellular forms, and their relation to more highly 

 developed plants, a lethargy appears to have seized upon 

 the minds of Algologists ; a calm prevails and more than a 

 decade passes before other explorers enter the field more or 

 less imbued with the spirit of the newer thoughts ; from time to 

 time larger or smaller contributions made their appearance. 



At the present date we have valuable papers from Borzi, of 

 Messina, Italy ; from Cienkowski and Faniinzin, of Eussia ; from 

 Hansgirg, of Bohemia, and Schaarschmidt, of Hungary ; from 

 Kirchner, Klebs, Eichter, Sachs, and others, of Germany ; from 

 Eostafinski, of Poland ; from Sirodot, of France ; from Wille, 

 Wittrock, Lagerheim, and others, of Sweden. Valuable as these 

 papers are. few appear to have traced the progress of growth in 



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