304 



by Ryder SjArillum osirearum, and supposed to be tlie Trypanosoma haViiani of Certcs. 

 The author of this ropfirt believes that this is ideiitieal with the eytohelniiiith 

 observed by him, and that until its life history is better known it can not be assigned 

 to any particular genus and species.] 



(21) These cytohelniinths are bred in a structure \vhich is or resembles the 

 "crystalline rod," a flexible, gelatinous structure, shaped like a nematode worm, 

 al)out an inch long, and-situated in a loop of the intestine known as the "pyloric" 

 portion. 



(hjHier economics. — (22) Oysters that are ready to spawn, if «'ooked soon after 

 removal from the sea bed, are extra good and palatable food. 



(23) Oysters in spawn deteriorate more rajiidly than at any otlier season, at the 

 same temperature. 



(24) The warmth of sunmier acts upon oysters as upon other meats, especially fish, 

 to produce ra]iid decay. 



(25) Oysters in market should be under stringent inspection. 



(26) Oystermen should not be rc(iuired to freshen oysters; this should be done by 

 the caterer just Ix-fore cooking or serving. 



(27) Oystermen should not be hampered bylaws limiting the time or manner of 

 taking or selling oysters. 



The spermatozoa. — (28) Spermatozoa removed from a rii)e male oyster and infused 

 into sea water, begin a very active dancing motion either at once or after a "latent 

 period" of a few minutes. 



(29) The length of time an oyster has been out of water often determines whether 

 a latent period is i>reaent. (Post marine age in i>ro]»ortii»i to its length tenils to]>ro- 

 duce this ])eriod.) 



(30) Tln' s]>enuatozoa survive the death of the oyster for a )>erio<l inversely ])ro- 

 portional to tbe length <>f tiiue which has elapsed b«-tweeii the taking of the oyster 

 from its bed and the artiticial o]ieiiing of the s:ime. 



(31) The activity of the sperniato/i>a lasts during :» p<riod the length of which 

 dei>ends on wlntlier .n l.iteiit period is present or not. the jiostiuarine age of the oyster, 

 the density of the water, the tem)ierat ore, tlu- ]»resence or absence of eggs, the age of 

 the eggs if i)resent, and whether the oyster has been freshened or not. 



(32) Oysters with latiiit period have siiermatozoa witii decrejised periods of 

 activity. 



(33) Fresh sjiermatozoa in their native sea water are active over 5 hours. 



(34) This jieriod is shortened in i»ro]»ortion to the ]iostmariiie age, in which {a^ 

 the number of iliiys before the oyster is opened count as nearly equal in intluenci 

 to (/>) those that have elajised since thi' oyster was opened. (Hy the end of a week 

 the period is reduced to a quarter of an lumr. but (c) conditions of temperature 

 and moisture atlect the r<\sult. The above exi)eriments were performed ujton oysters 

 subjected to an average of 7.'»^ V., ami moilerately sliielded from evajioratiim aftei 

 o]iening. ) 



(3r>) Densities of salt water above 2 ]ier tent shorten the active jieriod to about a 

 quarter of aji hour, when 3^ per cent is reached. 



(36) Dtiisities weaker th;ni IJ per cent (i>r thereabouts) shorti'U the period to the 

 same extent when one fourth ]ier cent is reached. 



(37) I'ostmariue age tends to shift the iqitimum strength of solution up the scale. 

 For oysters nearly a week old the o])timnm is above 3 per c<'nt iustead of being 

 below 2 i)er cent, as for fresh sjienuatozoa. 



(.38) Increase of teni])erature increases the activity but shortens the perio<l. The 

 practical limit (a period of a few minutes duration) is reached between KHV and 

 110^ F. 



(39) Tlie o])timum temperature for spermatozoid activity lies, roughly estimated, 

 at 85^. (Lower limits not yet ascertained.) 



(40) When spermatozoa are infused into water containing eggs their activity is 

 increased, but the period is shorted oue half. 



