140 DE. BRETT ON' THE FLUKE IN SHEEP. 



after a good meal, it is dark brown or brownish black ; if nearly- 

 empty, yellowish brown. If taken from the liver, it turns pale and 

 almost white. It has been calculated that the uterus of the fluke 

 may contain 40,000 eggs, and some sheep may have 1,000 flukes, 

 so that there may be 40,000,000 fluke's eggs in one sheep. The 

 fluke is hermaphrodite. It seems that the eggs have a good deal of 

 vitality ; some have been kept for tWo years, and yet they retained 

 their vitality. They are the one hundred and eightieth of an inch 

 long, and three hundredths broad. It is thought that the eggs having 

 passed from the sheep on the ground give rise to ciliated embryos. 

 Each egg may contain flve or six embryos, so that a sheep may 

 contain two hundred millions of possible flukes. These embryos 

 are ciliated and free swimming, and they exhibit the figure of an 

 inverted cone. After the lapse of a few days the cilia fall off, the 

 embryo then assuming the character of creeping larva {Planulce — 

 Cobbold). 



Plukes are parasitic to mammals, birds, fishes, reptiles, and even 

 to invertebrate animals. T'hey have been found in the horse, more 

 often the ass, the ox, and in some twenty instances in man. It is 

 supposed that after a time the embryos of the fluke become encysted, 

 in which state they have been called Cercaria, and that they may 

 enter the bodies of some kinds of snails, or remain on the herbage, 

 and be eaten by sheep ; and as they do not in ruminants go into 

 the true stomach at once, they have time to become developed, and 

 then they go into the liver and become flukes. It seems to me that 

 all the possible changes and metamorphoses that flukes may undergo 

 are not fully known ; and it is possible that there may be changed 

 forms yet to be discovered. 



If the microscopic object which has been seen in the muscle of 

 rotten sheep proves to be a fluke in otie of its forms, the knowledge 

 of this fact will greatly add to our knowledge of the natural history 

 of the Distoma hepoticum. My attention was first called to it by 

 Dr. Mason, Medical Ofiicer of Health for tontypool, and perhajis 

 I had better quote his wards. Se says: "It so happened that I 

 hoard that a lot of sheep had been bought in Monmouth market 

 for 2s. Q)d. and 3.s. %d. each, and that many would find their way 

 to our town (Pontypool); 1 asked my inspector to watch the 

 slaughter-houses, and give me word if he saw any suspicious- 

 looking sheep. He informed me that forty ' dickey ' sheep were 

 to be found in one slaughter-house, and not one liver. (The livers 

 had been removed by the butcher.) 1 visited the slaughter-house, 

 and there saw the worst lot of mutton I had ever beheld. I 

 ordered my inspector to seize the lot pending my investigation. I 

 ordered each sheep to be numbered and a sample to be cut out of 

 each, and to be numbered also. I then proceeded to find out if the 

 microscope could not reveal to me something reliable and tangible 

 to warrant me in condemning these sheep. After many specimens 

 had been examined, I was astonished to find a peculiar-looking 

 parasite in the muscular fibre, always having the same appearance, 

 the worst-looking meat always having the most parasites, the 



