448 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Protophyta. 



a. Schizopliycese. 



New Genera of Protococcoideae.* — From the plankton of a well in 

 Denmark, Prof. E. Chodat describes the following three new genera of 

 Protococcoideae : — Lemmermannia, founded on Tetrapedia emarginata 

 Schroed. ; Mofmannia, cells united into cocnobes of four individuals, 

 each containing a pyrenoid, springing from a membranaceous hyaline 

 tube ; Cateria, cells cylindrical, narrower in the middle, membrane 

 attached to both parts by a ring. 



Phormidium.f — Dr. L. Macchiati gives full descriptions of the two 

 species of this genus of Oscillatoriacese, P. uncinatum and P. autumnale, 

 one found in a mineral spring, the other on rocks and stones. 



£. Schizomycetes. 



Hereditary Variation of Microbes. J — Prof. M. W. Beijerinck re- 

 marks that it has been frequently noticed that bacteria cultivated in the 

 laboratory exhibit in the course of successive cultures marked variations 

 which are so different from the original that, had their developmental 

 history been unknown, they might have been considered with some 

 certainty to be different species. These changes may be classified 

 under three heads, viz.: — Degeneration, Transformation, and ordinary 

 Variation. 



Degeneration may be regarded as the gradual impairment of growth 

 affecting an organism by repeated cultivation. In transformation a 

 change affects all the members of a culture, some definite characteristic 

 being lost, and, possibly though not necessarily, being replaced by another. 

 The most common change is ordinary variation. With this the majority 

 of the culture remains unaltered, while a few individuals acquire new 

 characters and are distinguished as variants. These correspond to the 

 " races " of cultivated plants, and retain their newly-acquired characters 

 permanently, though subject to occasional reversion. Variants may 

 originate suddenly, possibly from unequal fission of the dividing cell, 

 but in most instances it is a gradual process, the stages or subvariants 

 being connected with the original form by transitional phases. Sub- 

 variants occur only in small numbers, and either show a disposition to 

 revert to tbe original form or to continue to produce variants. Yet by 

 careful selection of colonies these variants may be retained. Numerous 

 examples are quoted by the author, but for these the original should 

 be consulted. 



Chemistry of Bacteria.§ — E. Bendix obtained a pentose from tubercle 

 bacilli by boiling the dried organisms with a 5 p.c. solution of hydro- 

 chloric acid. The solution reduced alkaline copper solutions, gave the 



* Bull. Herb. Boiss. See La Nuova Notarisia, xii. (1900) p. 41. 



t Bull. Soc. Bot. Ital., 1901, pp. 13-20. 



X Kon. Akad. v. Wetenscbappen, Amsterdam, 1900. See Centralbl. Bakt., 

 2 ta Abt., vii. (1901) pp. 363-4 ; also Arckiv. Ne'erland. Sci. exact, et nat., iv. (1901) 

 pp. 213-30 (5 figs.). 



§ Chem. Centralbl., 1901, i. 406-7. See Journ. Chem. Soc., lxxx. (1901), Abstr. 

 ii. p. 206. 



