88 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Protophyta. 

 o. Schizophyceae. 



Richelia, a New Genus of Cyanophyceae.* — In plankton from the 

 Indian Ocean, J. Schmidt finds, within the cells of certain diatoms, a 

 blue-green alga which he names BicJtelia intracellularis g. et sp. n. The 

 genus is distinguished from Microchsete by the absence of a sheath and 

 by its intracellular habit ; and the author states that it is the first 

 recorded example of a cyanophyceous alga living within the cells of the 

 host. 



Pilg'eria, a New Genus of Chroococcaceae.f — Under this name W. 

 Schmidle describes a new genus of blue-green Algse from Brazil, con- 

 sisting of polyedric closely associated cells, forming small hollow 

 spheres not enclosed in jelly, the cells being empty or filled with jelly. 



#. Schizomycetes. 



Proteolytic Power of Bacteria.:}: — Dr. E. Cacace shows that when 

 bacteria decompose proteids, protalbumose, deuteralbumose, and pepton 

 are formed. But when bacterial action has attained to an advanced con- 

 dition, the products of proteid decomposition may be wanting. Proteo- 

 lysis is practically 1he same in all living animals. The foregoing 

 results were obtained by cultivating Sarcina aurantiaca, Bac. anthracis, 

 and Staphylococcus pyogenes aureus on gelatin and on blood-serum, and 

 submitting the products to chemical examination. 



Reaction of Bacteria to Stimuli.§ — H. S. Jennings and J. H. Crosby 

 describe the movements of Spirillum volutans when exposed to the influ- 

 ence of oxygen, light, and chemical stimuli. When the microbe reaches 

 the extremity of the area in which it is swimming and comes in contact 

 either with an area, say, devoid of oxygen or containing, say, salt, it re- 

 verses its movement and swims back in the opposite direction. This 

 reaction is termed the ractor reflex. The movement is comparable to 

 that of the ciliate Infusoria, but differs therefrom in that the bacterial 

 motor-reflex consists merely in a reversal of the direction of the movement, 

 without subsequent return to the original direction except as a response 

 to a new stimulus. The reason is that there is no difference between 

 the bacterial ends while the infusorian has a fore and aft. 



Effect of Nitrates on the Shape of Certain Bacteria. || — W. C. C. 

 Pakes describes the action of various percentages of nitrates in ordinary 

 broth or broth cultures without pepton, containing quantities of nitrate 

 from 1-10 p.c, upon certain bacteria. With B. typhi abdominalis the 

 presence of nitrate causes a thickening of the rod, imparting a Clos- 

 tridium-like appearance. With greater amounts the thickening increases, 

 the rodlet shortens until finally (6 p.c.) a yeast-like form is arrived at. 

 With B. coli communis the changes are less marked, the yeast-like forms 

 are absent, the bacilli are merely thickened here and there, but form 



* Hedwijriu, xl. (1901) Beibl., pp. 112-5 (1 fig.). 

 t Tom. cit., p. 45 (1 pi.). 



I Centralbl. Bakt., 1" AW., xxx. (1901) pp. 241-8. 

 § Amer. Journ. Pliysiol.. vi. (1901) pp. 31-7. 

 || Trans. Path. Soc, Hi. (1901) pp. 246-7. 



