November 19, 1915] 



SCIENCE 



727 



No chemical tests were made for the presence 

 of cyanide. Wesley P. Flint 



State Entomologist's Office, 

 XJrbana, III., 

 August 6, 1915 



A NEW mitotic structure 

 In the Journal of the Royal Microscopical 

 Society, April, 1915, Mr. E. Sheppard, 

 F.E.M.S., published a paper entitled " A New 

 Mitotic Structure Disclosed as the Eesult of 

 New Technique." He describes at the ends of 

 the dividing chromosomes " bead-like chroma- 

 tin extensions " where the spindle fibers are 

 attached. I want to draw his attention to the 

 fact that these structures are well known to 

 cytologists and that there is no special tech- 

 nique needed for their disclosure. My ovm ex- 

 perience is that they are most extremely de- 

 veloped in the maturation divisions of Tre- 

 matodes. I have figured them in my paper 

 " Die Chromatinreifung der GescWechtszellen 

 des Zoogonus mirus, etc.," Arch. Zellforschg., 

 Vol. 2, 1908. Better figures are found in 

 Gregoire's publication, based on the same 

 slides " La reduction dans le Zoogonus mirus, 

 etc.," La Cellule, 25, 1909. He calls these 

 structures " renflement d'insertion." For 

 Fasciola hepatica they are described by A. 

 Schellenberg, " Ovogenese, Eireif ung und 

 Befruchtung von Fasciola hepatica Arch. 

 ZeUforschg.," Vol. 6, 1910, and I know their 

 presence in some other trematodes. 



E. GOLDSCHMIDT 



A METHOD OP MAINTAINING A SUPPLY OP PROTOZOA 

 FOR LABORATORY USE 



One of the difficulties that confront the 

 teacher of elementary biology, especially in 

 those institutions where a large number of 

 students must be provided for, is that of ob- 

 taining a satisfactory supply of protozoa, espe- 

 cially of such forms as Ameha, Euglena and 

 Paramecium. I have overcome this difficulty 

 in such a simple manner that it may be worth 

 while to state briefly how I keep a supply of 

 these forms on hand. Four years ago I ob- 

 tained from a pond some water and rubbish in 

 which were present a few individuals of' 

 Ameha, Euglena and Paramecium. I pre- 



pared a culture made by boiling a handful of 

 hay in about a half-gallon of water until the 

 liquid assumed a dark brown color. This with 

 a part of the hay was placed in a two-quart, 

 cylindrical battery jar and permitted to stand 

 open in the laboratory for twenty-four hours. 

 The jar was then covered loosely with a pane 

 of glass and set aside till bacteria had formed 

 a scum over the surface of the liquid. The 

 pond water and rubbish were then added and 

 the jar still covered was set in a north window 

 of the laboratory. 



In a short time an abundance of Para- 

 mecia was present in the culture. The 

 Euglenw and Amehce multiplied more slowly, 

 but at the end of six months the jar was 

 swarming with these two forms, while the 

 Paramecia had decreased in number and were 

 to be found chiefly at the bottom of the jar. 

 Such a culture will usually afford a good 

 supply for a year but I prepare a new culture 

 every six months and stock it from the old 

 one. By this method I have for the past four 

 years kept on hand an abundant supply of 

 these protozoa without going outside of my 

 laboratory. At the opening of college I have 

 on hand a culture newly prepared, in order to 

 have an abundance of Paramecia, a second 

 culture six months old and a third one year 

 old. The hay infusion and the decomposing 

 vegetable matter in the jar seem to furnish, 

 suitable food for the bacteria and Euglena; 

 Paramecium feeds on the bacteria and Ameha 

 on the encysted Euglena. Eotifers and a host 

 of other protozoan forms abound in the cul- 

 tures but the three forms most used in labora- 

 tory exercises are always present in abundance. 

 In my laboratory I find it necessary to keep 

 the culture in a north window ; direct sunlight 

 is not only not necessary but decidedly harm- 

 ful, due probably to the heat rather than the 

 light. J. B. Parker 



Biological Laboratokt, 



Catholic Univeesity or America 



QUOTATIONS 



SCIENCE IN NATIONAL AFFAIRS 



"We printed last week a valuable address by 

 Professor J. A. Fleming on " Science in the 



