In the species of Vibrio which infests the grains of wheat and occasions the destructive disease called Ear-cockle or Purples, Mr.Bauer found the ova arranged between the alimentary canal and the integument, in a chaplet or moniliform oviduct which terminated by a bilabiate orifice at a little distance from the caudal extremity of the body. The ova are discharged at this orifice in strings of five or six, adhering to each other. Each egg is about nth of an inch long, and or in di ameter: and they are sufficiently transparent to allow of the young worm being seen within: and the embryo, in about an hour and a half after the egg is laid, extricates itself from the egg-coverings. Of the numerous individuals examined by Mr. Bauer, not any exhibited external distinctions of sex, and he believes them to be hermaphrodites.
In the Anguillulu aceti, or common Vinegar eel, Dory St. Vincent has distinguished indi viduals in which a slender spiculum is pro truded from the labiate orifice corresponding to that above described from which the ova are extruded ; these individuals he considers to be males ; they are much less numerous than the females ; are considerably smaller ; and the internal chaplet of ova is not dis cernible in them. In the female the ova are arranged in two series on each side of the alimentary canal, and the embryo worms are usually seen to escape from the egg-coverings while yet within the body of the parent, and to be born alive. Ehrenberg figures the two sexes of Anguillulafiuviatilis in his first trea tise on the Infusoria (tab. vii. fig.5.") The granular testis and iotromittent spiculum, which is single, are conspicuous in the male; the ova in the female are large and arranged as in Anguilluta aceti. Such an organization, it is obvious, closely approximates these higher Vibrionidre to the nematoid Entozoa, as the Ascaridcs and O.ryuri, and further researches on this interesting group will doubtless lead to the dismemberment of the Oxyuroid family from the more simple Vibrionide, as the genera Bacterium, Spirillum, and Vibrio, with which they are at present associated.
To the group composed of the three last named genera, the microscopic parasite of the human muscles, termed Trichina Spirulis, is referrible4 This singular Entozoon I discovered in a portion of the muscles of a male subject, which was transmitted to me for examination, at the beginning of 1835, by Mr.Wormald, Demon strator of Anatomy at St. Bartholomew's Hos pital, on account of a peculiar speckled ap pearance of those parts. This state of the muscles had been noticed by that gentleman as an occasional but rare occurrence in subjects dissected at St. Bartholomew's in several pre
vious years.
The portion of muscle was beset with minute whitish specks, as represented in the subjoined cut (fir. 531: and in fourteen subsequent instances which have come to my knowledge of the presence of this entozoon in the human subject, the muscles have presented very similar appearances. The specks are ced by the cysts taining the worm, and vary, as to their tinctness, according to their degrees ofopacity, whiteness, and ness.
The cysts are very readily detected by gently compressing a thin slice of the infect ed muscle between two pieces of glass and ap plying a magnifying power of an inch focus. They are of an elliptical figure, with the extremi ties more or less attenuated, often unequally elongated, and always more opaque than the body or intermediate part of the cyst, which is, in general, sufficiently transparent to shew that it contains a minute coiled-up worm.
The cysts are always arranged with their long axis parallel to the course of the cular fibres, which probably results from their yielding to the pressure of the contained worm, and becoming elongated at the two points where the separation of the muscular fasciculi most readily takes place, and offers least re• sistance; and for the same reason one or both of the extremities of the cyst become from repeated pressure and irritation thicker and more opaque than the rest. • That the adhesive process in the cellular tissue, to which I refer the mation of the cyst, was most active at the extremities of the cyst is also evinced by the closer adhesion which these parts have to the surrounding cellular tissue. The cysts measure generally about 20 t h of an inch in their longitudinal, and thth of an inch in their transverse diameters : like other cysts which are the result of the adhesive tion, they have a rough exterior, and arc of a laminated texture.
The innermost layer (fig. 54), however, can sometimes be detached entire, like a distinct cyst, from the outer portion, and its contour is generally well marked when seen by trans mitted light. By cutting ofl'the extremity of the cyst, which may be done with a cataract needle or fine knife, and gently pressing on the opposite extremity, the Trichina and the granular secre tion with which it is surrounded, will escape ; and it frequently starts out as soon as the cyst is opened. But this delicate operation requires some practice and familiarity with microsco pical dissection, and many attempts may fail before the dissector succeeds in liberating the worm entire and uninjured.