198 .SUMMARY OF CURRENT RESEARCHES RELATING TO 



Lichens. 



(By A. Lorrain Smith, F.L.S.) 



Verrucarise of Central Europe.* — Hermann Zschacke has begun a 

 study of this group of lichens, and he takes first the genus Staurothele, 

 in which green algal cells are enclosed in the hymeniurn. He makes 

 use of the form of these cells in his classification of the different species. 

 The thallus is crustaceous and superficial or entirely immersed in 

 the rock, and the perithecia are also superficial or immersed. Other 

 means of dividing species are afforded by the number of spores in the 

 ascus ; there are either 1 or 2 (Oligosporse), or there are 4-8 (Pleiosporx). 

 Zschacke has worked on herbarium material to a large extent. 



Mycetozoa. 

 (By A. Lorrain Smith, F.L.S.) 



Myxomycetes from the Jura Mountains-! — Ch. Meylan reports 

 fifty-one species and varieties from the Jura, with various critical 

 remarks. He was able to follow the development of Colloderma ocu- 

 latum from plasmodium to sporangium. The plasmodium is a small 

 colourless jelly-like mass which takes a spherical form. In the centre 

 there appears a darker part which eventually becomes the round dark 

 sporangium. Several new species and varieties are described. 



Schizophyta . 

 Sehizomycetes. 



Streptococcus-pneumococcus Transmutations.! — E, C. Rosenow, 

 by means of inoculations into animals, growth in symbiosis with other 

 organisms, cultivation under high oxygen pressure and upon hypertonic 

 and hypotonic media, and treatment with filtrates from ascites broth, 

 has brought about mutual transmutation between three types of organ- 

 ism, Streptococcus heemolyticus, Streptococcus viridans, and pneumococcus. 

 Twenty-one strains originally isolated as hsemolytic streptococci have, 

 in one way or another, been converted into S. viridans, three into 

 S. viridans and pneumococci, and one into S. mucosas. Seventeen 

 original S. viridans cultures have been changed into pneumococci and 

 three also into S. mucosus, ten have been converted into hsemolytic 

 streptococci, eleven pneumococci have been converted into hemolytic 

 streptococci, seven into S. viridans ; the streptococci from three of 

 these strains by animal passage acquired all the characters of the rheu- 

 matic streptococcus, S. viridans, and back into pneumococci. Whenever 

 mutation was observed, cultures of each main variety were obtained from 

 single organisms by the Barber method. 



* Hodwigia, liv.' (1913) pp. 183-98 (1 pi.). 



t Ann. Conserv. Jard. Bot. Geneve, xv.-xvi. (1913) pp. 309-21. See also Bot. 

 Centralbl., cxxiv. (1913) pp. 545-6. 



X Journ. Infect. Diseases, xiv. (1914) pp. 1-32. 



