1898.] MICROSCOPICAL JOURNAL. 85 



which sections are desired. When the balsam is cold and 

 firm the g"lass is used as a handle by which to hold the ob- 

 jects while g-rinding-. A flat surface may be g-iven them 

 as they lie in the balsam by rubbing- with a hone. Heat 

 the glass to release the mica by softening- the lower film of 

 balsam, lift the mica with forceps and turn it over on an- 

 other g-lass which has been provided with balsam. The 

 g-round surface is now downwards and the other side may 

 be g-round as desired. 



Protozoa.— A culture medium free from bacteria is 

 made thus: Suspend 30 grammes hay in one litre water, 

 add 1>4 g-rammes powdered calcium hydrate, shake well, 

 heat in oven 24-36 hours, filter, precipitate the calcium 

 with phosphoric acid. Mix the filtrate with equal parts 

 buillon, alkalized with soda. Add 1^ g-rammes ag-ar. 



Phosphorescence. — In case of the limans of Odessa 

 which emit phosphorescenct lig"ht the phosphorescence is 

 due to an infusorium, g-lenodinium, whose protoplasm 

 emits the light. 



Fish. — Most of their food being microscopical org-anisms, 

 the multiplication of fish is dependent not so much on the 

 taking- and hatching of eg-g-s as on understanding- and con- 

 troling the food supply; yet the Fish Commissions often 

 hatch and plant egg-s in utter ig-norance of this phase of 

 the subject. 



Archaeological. — Prof. Nicholson of Lewes, Eng-land 

 recently found on an ancient bronze implement certain 

 small excrescences which were centres of rapid oxidisa- 

 tion but of recent appearance. He scraped off and exam- 

 ined the material under a 1-4 and 1-7 inch objective discov- 

 ering- that the oxidisation was due to bacteria which 

 swarmed in it. He asks for similar observations and a 

 method of sterilization. 



Dust. — A shower of microscopic dust was reported in 

 February off the West coast of Africa and at Leguna, 

 Teneriffe. The dust was grey and extremely fine. It 

 deposited upon every object and rendered the drinking- 

 waters salty and colored as by oxide of iron. The sun's 



