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 g-lass to release the mica by softening- the lower film of 

 balsam, lift the mica with foi'ceps 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 ground as desired. 



Protozoa, — A culture medium free from bacteria is 

 made thus: Suspend 30 g-rammes hay in one litre water, 

 add 1^ 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 

 bullion, 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 lig-ht. 



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 eg-g-s in utter ignorance 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 Leg-una, 

 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 



