752 REPORT OF COxMMISSIONER OF FISH AND FISHERIES. [4] 



artificial elements the mussel resists less than the venuses; and among 

 these latter the reticulated venus or clovisse shows less resistance than 

 the palourde {Venus deeussata), which exhibits a remarkable degree of 

 resistance. In the solution of sulphate of magnesia, for instance, the 

 mussel succumbed after ten days, the reticulated venus-shell after fifteen, 

 whilst the palourde was still alive after sixty days. These proportions 

 were very nearly maintained in the other solutions relatively to the 

 duration of life in these mediums. 



Below is given the result of these experiments as regards the palourdes 

 ( Venus decussata). Five specimens of this kind w^ere on the 10th Janu- 

 ary, 1882, i^laced, under the same conditions, in each of the different 

 solutions mentioned above. The same care was bestowed on all of them, 

 and they were properly aerated every day. At the same time a certain 

 number of these mollusks were placed, near to the former, in vessels 

 containing natural sea-water. 

 January 10. Experiments commenced with the palourdes. 



25. They succumbed in the ioduret of potassium. 

 February 10. They succumbed in the chloride of potassium. 



15. They succumbed in the air. 



IS. They succumbed in the sulphate of potassium. 



18. They succumbed in the common water. 



20. They succumbed in the solution No. 10. 



20. They succumbed in the bromide of potassium. 



20. They succumbed in the chloride of magnesium. 



25. They succumbed in the Vichy water. 



22. They succumbed in the chloride of sodium. 



22. They succumbed in the solution No. 12. 



24. They succumbed in the solution No. 9. 

 March 10. They succumbed in the sulphate of magnesia. 



10. They succumbed in the solution No. 11. 



15. Some palourdes are still living in the sulphate of soda. 



15. The palourdes placed in the sea- water are alive. 

 Observations on these facts. — It appears from these experi- 

 ments that, in spite of the possibility of shutting thems Ives up between 

 their valves, the venuses yield to the action of the surrounding mediums, 

 since their power of resistance is not equal. 



Salts of i)otash seem much less favorable than the salts of magnesia, 

 and especially than salts of soda. Life ceased first in the ioduret, the 

 bromide, the chloride, and the sulphate of j^otassium, and in solution 

 No. 10, the prevailing element of which is chloride of i)otassium. 



The salts of soda and magnesia still maintained life when the animals 

 had succumbed in the salts of potash. Solution No. 9, for instan<;e, the 

 principal element of which is chloride of magnesium, i>reserved its in- 

 habitants alive much longer, and the same applies to the sulphate of 

 magnesia alone and in solution No. 11. 



The resistance of the palourdes in the Vichy water shows the favor- 



