588 SUMMARY OF CURRENT RESEARCHES RELATING TO 



weight is sent down cord A at desired depth, when position Y is 

 obtained and nothing enters or gets out of the net. It is easy to trawl 

 in fast in this position. The net can be made of any size. 



Preparing Agar.* — K. Rosam states that the following procedure 

 prevents the too rapid setting of agar, and facilitates nitration. Pow- 

 dered agar is treated for about five minutes with 10 p.c. acetic acid ; it 

 is then placed on a sieve and the acetic acid washed out with running 

 water. Thus prepared, agar is rapidly filtered, has a low melting-point, 

 and solidifies at 85° C. It may be stocked dry, and will keep for quite 

 a long time. The filter-paper recommended is Schleicher and SchiiU's 

 No. 601. 



Cultivation of Algse.f — Th. Frank obtained pure cultures of 

 Chlamydomouas tingens by inoculating agar with single cells. He also 

 used Knop's medium, which consists of 4 parts calcium nitrate and 

 1 part potassium nitrate, magnesium sulphate, potassium monophos- 

 phate, and a trace of iron sulphate. Made up with distilled water, this 

 medium has a slightly acid reaction, and the free acid it contains corre- 

 sponds to about 0'033 p.c. phosphoric acid. When used in concentra- 

 tions varying from 0*05 to 3 p.c, the results obtained were good. 

 Besides agar and Knop's medium, cultivations were made successfully 

 on gelatin and on clay plates saturated with nutrient fluid. 



Cultivation of Anaerobes. % — D. J. Hamilton describes a method 

 which aims at the exclusion of any atmosphere whatever. The first 

 step is to encourage sporulation, and this is done by incubating (at 37° 

 to 38° C.) the organism in the liquid upon which it is found growing 

 naturally within the animal body. The fluid is removed in a Pasteur's 

 pipette ; this is then sealed off, and the tube incubated for 24 to 48 

 hours. By this means the organism is obtained in the sporing state. 



The medium used is glucose-pepton-beef-tea. This must be boiled 

 and filtered until precipitation of phosphates ceases. The reaction 

 must be distinctly alkaline to phenolphthalein. The medium is de- 

 canted into test-tubes or flasks, and sterile olive-oil to the depth of 

 1*5 cm. is then poured over the surface. The tubes or flasks are 

 sterilised again on three successive days ; on the first day for f hour, 

 on the second and third day for J hour. 



The spores are inoculated by drawing up some of the spore-con- 

 taining fluid in a Pasteur's pipette, which is plunged into the beef -tea 

 and some of the contents blown out, care being taken not to empty the 

 tube lest any air might enter. The plug is then readjusted, and the 

 vessels heated in a water-bath at 80° C. for 20 minutes, to kill off any 

 non-sporing contaminations. If the organism be contained in a tissue 

 a minute piece is snipped off and dropped into the tube or flask. 

 After the last-mentioned heating the vessel is cooled down quickly in 

 running water. The inoculated vessels are then incubated. Within 

 24 hours, as a rule, germination is in full activity, and the growth may 

 be examined by withdrawing some fluid by means of a sterilised pipette. 



* Centralbl. Bakt., 2 te Abt, xii. (1904) p. 464. 

 t Bot.Zeit., lxii. (1904) pp. 153-88 (1 pi.). 

 1 Brit. Med. Journ., 1904, II. pp. 11-2. 



