24 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



oysters are grown in Europe. I now call to mind the extensive deposits 

 of ooze on the bottom of a cove at Saint Jerome's Creek, where deposi- 

 tion over a limited area has been going on for many years until in some 

 places the ooze is 9 feet deep and utterly unfit as a bottom upon which 

 to plant oysters, because they would inevitably sink into the mud and 

 be smothered. In the moat around Fortress Monroe, which is in com- 

 munication with the Chesapeake Bay, there is also a very considerable 

 sedimentary deposit, few oysters being able to exist on the bottom, but 

 large numbers are attached as "natural growths" to the clean surfaces 

 of the walls on either side of the moat, to which the spat has at one time 

 and another aflSxed itself in such numbers, and there grown so rapidly 

 as to nearly cover the vertical and inclined surfaces of the massive 

 boundary walls. Ooze or sedimentary deposits of more than a very few 

 inches in thickness are therefore hurtful to growing adult oysters, while 

 a very thin film of a similar kind is fatal to the young oyster in its ex- 

 treme infancy or embryonic state immediately after fixation. Getting 

 rid of or i^reventiug such deposits is therefore of the very greatest im- 

 portance in the work of i)ractical oyster culture. 



Many oystermen are ready to affirm that some mud is a necessity in 

 the work of oyster culture; they in fact make bold to say that the ani- 

 mal needs a certain proportion of mud to feed upon. The origin of this 

 mistaken doctrine is probably to be sought in the fact that a few of the 

 more intelligent culturists have possibly noticed that the nearly black 

 ftecal matters of the animal consist almost wholly of a material which, 

 without critical examination, would be taken for mud molded into the 

 form of the internal cavity of the intestine. A little investigation will 

 serve to convince the most skeptical, however, of the utter absurdity 

 and irrationality of the hypothesis that oysters feed upon mud. In the 

 first place mud is not in any sense food, either vegetable or animal, and 

 whatever of ooze or sediment is found in the alimentary tract of the 

 oyster, or any other mollusk, was carried there accidentallj- together 

 with what was truly food in the form of minute animal or vegetable or- 

 ganisms, upon which it is also known that the oyster exclusively feeds. 

 It is well known to naturalists, moreover, that when one wishes to find 

 such minute living organisms for study with the microscope, they ai-e 

 not to be found buried in the mud, where they would as inevitably be 

 smothered and killed as the oyster itself, and from the same causes, 

 namely, interruption of respiration on account of the absence of oxygen, 

 and the exhalation from the ooze of jwisouous, asphyxiating gases. 

 Here is what a very eminent authority has said about the habits of cer- 

 tain minute organisms living in water : " The favorite habitation of 

 many kinds of Khizopods is the light superficial ooze at the bottom of 

 still waters, where they live in association with Diatoms, Desmids, and 

 other minute Algixj, which form the chief food of most of these little 

 creatures. They never penetrate into the deeper and usually black 



