THE INTERNATIONAL FISHERIES EXHIBITION. 197 



ii. Processes for rendering streams polluted by sewage and chemical 

 or other works innocuous to fish-life (illustrated by models and 

 drawings), 

 iii. Physico-chemical investigation into those qualities of salt and 

 fresh water which affect aquatic animals ; investigation of the 

 bottom of the sea and of lakes, shown by samples ; aquatic plants 

 in relation to fishing, &c. ; researches into the aquatic fauna 

 (animals of the several classes preserved in alcohol or pre- 

 pared, &c); apparatus and implements used in such researches. 

 5. Acclimatisation of Fish. 



These are all very important subjects, perhaps none more so 

 than that which relates to an investigation of the causes of disease 

 in fish and the means of cure. For the best essay on this subject 

 a special prize has been offered, which it is to be hoped will so 

 far stimulate research as to lead to valuable practical results. 



We need not now refer to the subjects of other essays for 

 which prizes wdll be given, for under the conditions long since 

 published by the Executive Committee all competitors are required 

 to send in their MSS. by the 1st May. On a future occasion, 

 should the accepted essays be printed, we may hope to refer to 

 them in detail. 



If one class of exhibits more than another can be said to have 

 a special attraction for naturalists, it is Class V., which contains 

 living representatives and preserved specimens of both maiine 

 and freshwater animals and plants. Specialists will find their 

 favourite groups here represented under natural conditions, and, 

 from the names of some of the exhibitors which have already 

 reached us, it may be anticipated that many of the collections 

 will be extremely good ones. 



It should be observed that up to the date of penning these 

 remarks the exhibits in this Class were not on view, nor were the 

 arrangements for displaying them completed. Hence it has not 

 been possible to furnish our readers, as we should like to have 

 done, with detailed descriptions of the more interesting objects, 

 the nature of which may be inferred from the following list : — 



Class V.— AQUARIA. 

 1. Specimens, Living (Marine and Fresh Water), Fresh, Stuffed or 

 Preserved, Casts, Drawings, and Representations of — 



a. Alga? to be arranged under genera and species, with localities appended. 



b. Sponges, in their natural state. 



