ZoBell — 28 — Marine Microbiology 



glass hypodermic syringe has been used by Dr. C. E. Renn at the Woods 

 Hole Oceanographic Institution. It is difficult to exclude water from a 

 cylinder fitted with a piston or plunger, especially at great depths, unless 

 equipped with a valve near the orifice. If such a cylinder could be made 

 absolutely leak-proof, the pressure of the water at great depths against 

 the walls of the cylinder may bind the plunger unless the walls are very 

 thick. 



Reyniers (1932) used a glass cylinder fitted on each end with small- 

 bore flexible rubber tubing to which cords are attached. When suspended 

 by the rubber tubing, the latter is bent at a sharp angle thereby sealing 

 the ends of the cylinder. After lowering the apparatus to the desired 

 depth, a second line is used to take the tension off the rubber tubing, 

 which permits the rubber tubing to straighten out, allowing the cylinder 

 to fill with water. This ingenious sampler has the disadvantage of requir- 

 ing two lines for its operation, and no provisions are made for excluding 

 water from the ends of the inlet tubes, a possible source of contamination 

 from the overlying water. 



The glass cylinder sampler described by Butkevich (1932a) has rub- 

 ber connections which are operated by a messenger-activated mechanism. 



Samplers having a capillary tube inlet: — Russell (1892) perfected 

 the evacuated glass bulb sampler of Massea (Fig. 2A) by fitting a small 

 flask with a glass tube, the end of which could be hermetically sealed. 

 Provisions were made for breaking the end of the tube by dropping a mes- 

 senger at the desired depth, thus permitting the flask to fill with water. 

 It is not necessary to close such a sampling bottle because when left down 

 until the water pressure on the inside is in equilibrium with that on the 

 outside, the tendency will be for water to be forced out of the bottle as it 

 is drawn toward the surface. Therefore there is no possibility of adven- 

 titious organisms entering the sample while being hauled to the surface. 

 The glass flasks are easy to clean, sterilize, and manipulate. Various 

 modifications of this device have been used by For tier and Richard 

 (1906), Kruse (1908), Parsons (1911), Issatchenko (1914), and others 

 (see Fig. 2). 



Wilson (1920) simplified the apparatus by using a large test tube 

 fitted by means of a rubber stopper with a capillary glass tube, the end of 

 which could be sheared off by a messenger-activated lever. Gee (1932a) 

 attached it to an Ekman bottle. To provide for collecting samples at 

 greater depths, he used a thick-walled test tube with the neck constricted 

 to prevent the rubber stopper from being pushed into the tube by the 

 hydrostatic pressure which increases with depth (Fig. 2D). Although 

 Gee recommended it for "critical work at great depths," ordinary 

 loo-ml. thick- walled test tubes are broken by pressures encountered at a 

 depth of 600 to 1000 meters. 



ZoBell and Feltham (1934) perfected a mechanism for breaking the 

 capillary tube. Correcting a fault inherent in the construction of earlier 

 models, the capillary tube was bent in such a way that the broken end of 

 the tube through which the water enters the sampler was a few inches 

 away from any part of the apparatus which might carry contaminating 

 organisms (Fig. 2E). 



After nearly ten years of experimentation with various kinds of de- 

 vices, ZoBell (1941c) described the J-Z bacteriological water sampling 

 bottle. It consists of a universal metal frame carrying the messenger- 



