THE VICTORIAN NATURALIST. 



a blue tint under the surface if scraped away. They are long, 

 oval, and have a thick shell, equalling in size tliat of the common 

 goose. The task of getting the nests into the hold of the schooner 

 was one of considerable difficulty. The largest secured measured 

 eighteen inches in diameter at the bottom, thirteen inches at the 

 top, and nine inches in height, weighing upwards of loo lbs. 

 Being a solid mass of mud, and dried only externally, it needed 

 only a slight jar to break the strongest nest into fragments. 

 However, six were safely got into tlie hold of the schooner. At 

 Nassau they were treated with a 'solution of gum arabic, which 

 Iiardened them, and, after being wrapped in plaster of paris band- 

 ages, were packed separately in large boxes, finally reaching New 

 York in excellent condition. 



Preserving Fluid for Microscopic Objects. — I would like 

 to bring under the notice of microscopists a preserving medium 

 known as Ripart and Petit's fluid, having the following composi- 

 tion : — Camphor water (not saturated), 75 parts ; distilled water, 

 75 parts; glacial acetic acid, i part; acetate of copper, 0.3 part; 

 chloride of copper, 0.3 part — which I have found extremely 

 useful. To the recipe I have sometimes added formalin in the 

 proportion of i per cent., or a trace of osmic acid at the time of 

 using. Material may be mounted in this fluid on micro slides, or 

 kept immersed in the fluid in small vials away from the light, and 

 a little taken out for examination under the microscope when 

 required. The form and cellular contents will be faithfully 

 preserved, and the colour to a very considerable extent. — O. A. 

 Sayce. 



Oysters and Diatoms. — It has been observed that oysters 

 grow much more slowly on some beds than on others — that in 

 certain places they fail to fatten. These places were usually on 

 overcrowded beds, and sometimes good results could be secured by 

 transplanting or thinning out. Qualitative and quantitative study 

 of the diatoms (which constitute the food of oysters) on beds 

 where the oysters fattened well, and on other beds where 

 they fattened poorly, showed that the number of diatoms per litre 

 of water was very much greater in the former than in the latter. 

 It was therefore believed that if the supply of diatoms could be 

 increased on the unproductive beds the oysters on them would 

 grow and fatten. Experiments along these lines were recently 

 inaugurated at Lynnhaven, Va., under the immediate direction of 

 Dr. H. F. Moore, of the Bureau of Fisheries. A small cove was 

 selected where the bottom and the salinity of the water were 

 favourable but diatoms were scarce. Commercial fertilizers of 

 certain kinds were used to furnish food for the diatoms, and it 

 was very soon found that the latter greatly increased in abund- 

 ance, and lean oysters transferred to this cove fattened rapidly. — 

 Scientific American, i6th July, 1904. 



