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®n tbe Cultivation of 2)iatom9 b^ artificial 



fiDeane. 



By Dr. Miguel. 



Translated from Le Diatomiste. 



Chapter I. — The Ordinary Growth of Diatoms. 



TO cultivate any microscopic species it is necessary that the 

 conditions of its independent and voluntary reproduction 

 should be provided by the experimenter. 



Such an operation requires — 



I. — The formation of a nutritive medium, suitable for pro- 

 moting the development of the species. 



2. — The subsequent sowing of the microphyte, the multipli- 

 cation of which is desired. 



3. — Special precautions, without which the growth would be 

 endangered, and which consist essentially in promoting the life of 

 the microphyte, either in avoiding the many things which would 

 injure it, or which would increase too greatly the action of such as 

 stimulate it. 



I. — The Cultivation of Diatomsin a fresh-water Preparation of 

 the Nutritive medium. Besides the natural medium for the growth 

 of diatoms, which is water, it is necessary to provide them with 

 two kinds of food : Saline food and Organic food. 



The common water of springs and streams are not usually 

 sufficiently charged with mineral and organic substances to favour 

 an abundant growth of diatoms ; nevertheless in sowing diatoms 

 in common water, fully exposed to light, you can see produced at 

 the bottom of the vessel, especially if the vessel be of glass, little 

 yellow spots, formed exclusively of diatoms in course of multi- 

 plication. But these organisms soon exhaust the mineral and 

 organic constituents which are essential to their support, and its 

 growth is arrested. It is resumed and carried forward as soon as 

 these constituents are supplied ; how this is done we are about to 

 show. 



It is only after having studied repeatedly the action of different 

 salts that I have been able to establish a proper formula for 



