24 BIBLIOGRAPHY. 



respecting the developmental phenomena of the class in general is of the 

 utmost value. 



The same decade, conspicuous for the substantial progress effected 

 towards a more accurate and extensive knowledge of the Infusoria at 

 the hands of Stein, Claparede, and Lachmann, includes divers other 

 names which, although not similarly associated with the authorship of 

 separate treatises, hold a deservedly high place in the annals of infusorial 

 literature. That of Balbiani is especially noteworthy in this direction, he 

 having been the first, in the year 1858, to announce that the hitherto 

 supposed longitudinal fission of Paramecium aurelia and various other 

 animalcules, was not an act of division at all, but one of genetic or sexual 

 union, attended with complex internal changes, as detailed at length in the 

 chapter devoted to an account of the reproductive phenomena of this class. 



Max Schultze's name, though more intimately connected with the 

 history of the Rhizopodous section of the Protozoa, demands notice 

 here, he having in the years 1860 and 1861 developed and modified 

 to a marked extent the unicellular theory of the Infusoria first origi- 

 nated by Von Siebold. By this author the frequent absence from, 

 and non-essentiality of, a bounding membrane or distinct cell-wall to 

 many lower unicellular protozoic structures, was especially insisted on, 

 the probability also being suggested that many, such as Actinosphcerium 

 EicJwrnii, and others possessing a multiplicity of nucleus-like structures, 

 were composed of a greater or less number of wall-less cells indistinguishably 

 amalgamated with each other. Further, Max Schultze in his demonstration 

 that the soft plastic contents only, independently of an outer bounding 

 wall, constitute the very essence or essential factor of cell organization, 

 proposed to distinguish this soft and contractile substance by the charac- 

 teristic title of " protoplasm " in contradistinction to that of " sarcode," 

 introduced in a somewhat similar but narrower sense some years pre- 

 viously by Dujardin. With this author there also originated the brilliant 

 and fortunate conception that the cell-contents of all animal and vegetable 

 organisms were composed of a similar simple protoplasmic basis, such 

 forms again, in their simplest expression, as in an Amceba, consisting of 

 a mere animated speck or lump of undifferentiated protoplasm. Max 

 Schultze's interpretation concerning the probable composite structure of 

 certain Rhizopoda and Radiolaria received substantial confirmation at the 

 hands of Ernst Haeckel, in his magnificent monograph of the Radiolaria, 

 published in the year 1862. 



Stein, already mentioned as having in the year 1854 published an 

 important work devoted more especially to the organization of the Vorti 

 cellidae and their supposed associated Acinetce, gave abundant evidence 

 of continued activity in the same field by the production, in the year 1859, 

 of the first volume of the folio series still in course of progress, having as its 

 aim the description and illustration of all known infusorial forms. In this 

 volume Stein carried into practical application the new system of classifica- 



