864 



K. .(. ALLEN AND E. W. NELSON. 



The essential features of Miquel's method, as applied to 

 marine diatoms, are as follows : 

 Two solutions are prepared : 



Solution A. 

 Magnesium sulpliate . 

 kSodium cliloride 

 Sodium sulphate 

 Ammonium nitrate . 

 Potassium nitrate 

 Sodium nitrate . 

 Potassium bromide . 

 Potassium iodide 

 Water .... 



Solution B.^ 

 Sodium phosphate 

 Calcium chloride (dry) 

 Hydrochloric acid 

 Ferric chloride . 



\Yator 80 c.c. 



Forty drops of solution A and ten to twenty drops of solu- 

 tion B are added to each 1000 c.c. of sea-water, and the sea- 

 water is sterilised by keeping it at 70° C. for about twenty 

 minutes. 



According to Miquel it is also necessary to add " organic 

 nutritive material in the form of bran, straw, or filaments of 

 ^ " The preparation of sohition A presents no difficulty. Solution B 

 sliould l>e made up as follows : To tlie sodium phosphate dissolved in 

 40 c.c. of water are added first the 2 c.c. of hydrochloric acid, then the 

 2 c.c. of hydrous ferric chloride, and then the 4 grm. of calcium 

 chloride dissolved in 40 c.c. of water, taking care to shake the mixture, 

 which I call phospho-ferro-calcic solution. The addition of this last 

 solution to the maceration throws down a slight brownish flocculent 

 precipitate, formed for the most part of ferric oxide, which should be 

 carefully sepai'ated from the liquid used for cultivations." 



- '■ Acid chlorhydrique pur :\ 22"." Presumably meaning degrees 

 Baume = sp. gT. Il(i9. 



s i- Perchlorure de fer liqi;ide a 4-5°.'' As above = sp. gr. 1421. 



