70 SUMMARY OF CURRENT RESEARCHES RELATING TO 



When the Flagellate Anisonema acinus — having a relatively high 

 organization — is cultivated for many generations in a medium which 

 is slowly modified, for instance in fresh water to which a certain 

 amount of sea-salt is added, its structure is modified in proportion 

 as the concentration of the solution of salt is increased. The indi- 

 viduals become less developed, their size diminishes, and the feeding- 

 canal loses its former development. Numberless intermediate forms 

 between Anisonema acinus and its new, less developed representatives, 

 make their appearance, as well as between these and the still lower 

 Anisonema sulcatum, which would thus be but a lower organized 

 variety of the former. When the concentration of the medium in 

 which the Anisonema lives is carried on side by side with a change of 

 temperature of the medium, the transformation goes further on, and 

 the lowest Anisonema are transformed on the one side into alga-like 

 organisms, and in another direction into organisms which seem to 

 belong to the category of fungi. The individuals not only become 

 smaller, but they give rise also to a progeny long before reaching 

 their full size. Under the influence of the sun's rays the uncoloured 

 Flagellata acquire a new physiological function, and develope chlo- 

 rophyll. 



" We see thus," the author says, " the beginnings of two kingdoms, 

 animal and vegetable, radiating from one common stem. We see the 

 transformation of one of them into the other, not only in its morpho- 

 logical features, but also in its physiological functions, under the 

 direct influence of physical and chemical agencies. The saline solu- 

 tions, as compared with fresh water, diminish the size of the lower 

 organisms, and at the same time they contribute towards the develop- 

 ment of chlorophyll in the fresh-water algse, thus giving them, so to 

 say, a more vegetable character, together with an increased pro- 

 ductiveness." And further : " Whilst descending from Anisonema 

 sulcatum to a unicellular alga, we see the retrogressive development, 

 a simplification of organization ; we descend towards the plants con- 

 taining chlorophyll. . . . While descending from the same Anisonema 

 by another branch, we enter into the region of those lower organisms 

 which, under the influence of another medium, do not develope chloro- 

 phyll, and, having no nutrition from the air, derive their food from the 

 substratum ; they might be described as parasitic Ehizopoda, and 

 this the more, as from the fungoid form we can ascend, under some 

 circumstances, not only towards the amoeba-like uncoloured Flagellata, 

 but also towards the moving monad. On the contrary, by reversing 

 the physical agencies, we can arrive, from the unicellular alga, as 

 well as from the fungoid form, to an uncoloured form having the 

 structure of Anisonema." The researches of A. Giard, Cienkowsky, 

 and Famintzin, and some observations by E. Eay Lankester, seem to 

 be, in the author's opinion, in accordance with the above. 



Stein's 'Infusionsthiere.'* — The second half of Part III. of 

 Dr. F. Ritter v. Stein's well-known work on the Infusoria, has just been 



* Stein, F. Eitter v., ' Der Organismus der Infusionsthiere. III. Abth. 

 II. Halfte. Der Organismus der Arthrodelen Fiagellaten.' fol., Leipzig, 1883, 

 30 pp. and 25 pis. 



