•iSo 



G. 11. DKEW. 



described in detail by Mr. Matthews in the present mimber of the 

 " Journal of the Marine Biological Association of the United King- 

 dom. " so only a brief aceonnt of it will be given here (see p. 525). 



The apparatus employed by previous workers for obtaining samples 

 of water from the deep sea for bacteriological examination has either 

 consisted of some sort of water-bottle made of metal, or else of exhausted 

 glass bulbs, with a neck drawn out into a capillary tube, which could be 

 broken oft* at the depth from which a sample was desired. The use of 

 exhausted glass bulbs presents considerable ditticulties for depths as 

 great as 800 fathoms : the bulbs must be strong and very thoroughly 

 annealed, as otherwise the slight shock caused by breaking the capillary 

 neck is liable under the great pressure to make the bulb tly into small 

 fragments : another great disadvantage is the strong probability that 

 the sudden reduction in pressure to which the water is exposed, as it 

 enters the bulb, would immediately kill any bacteria in the water. The 

 employment of a metal water-bottle seemed undesirable in view of the 

 bactericidal action of metals : in order to settle this point some test 

 experiments were made with various metals to see if a suitable one 

 could be found. 100 c.c. of water from the Laboratory tanks at 

 Plymouth, diluted 1 in 100 with sterile sea-water, was exposed for six 

 hours to the action of about two square inches of various metals, 

 with the foUowiniT results : — 



Metal. 



Numbers 

 of plates. 



Number of colonies of bacteria devcl- 



i oping from 1 c.c. after plating on 

 i Peptone Agar. Counted after 10 days. 



Aluminium bronze 



Pure copper foil 



