224 THE director's report. 



not properly seasoned. It is a matter of common experience that a 

 sea-water aquarium cannot be got into good order for many months, 

 and it was not to be expected that the Plymouth Laboratory should 

 be exempt from the initial difficulties experienced by other institutions. 

 It was further said that we were obliged to add salt to bring the 

 water to the required density. This was done once, in August, 1888, 

 immediately after the opening of the Laboratory. It has never been 

 found necessary to do it since, and there is no reason to suppose 

 that it will ever be necessary to do it again. 



It is interesting to note that Dr. Dohrn,.the experienced founder 

 and director of the Naples Zoological Station, writing to Prof. 

 Lankester about the choice of a site for the Laboratory of the Marine 

 Biological Association, told him that the source from which the sea 

 water was derived was not of so much importance as the size of the 

 storage reservoirs, for no water that could be drawn from the sea 

 would be as suitable for hatching and rearing delicate marine or- 

 ganisms as that which had been for some time in the reservoirs. Our 

 experience proves the wisdom of Dr. Dohrn's advice. 



G. C. BOURNE. 



Plymouth ; March 4th, 1890, 



