440 



DISEASES OF THE BLOOD. 



and Eovelli afterwards found it in about 75 per cent, of the sheep 

 slaughtered at Catania, Sicily. 



Source of Infection. Clinical observation and analogy point to 

 unfiltered drinking water as the source of infection. 



Position of the Parasite. The worms are found in the veins 

 of the abdomen, the vena porta, vena linealis, vena renalis, and the 

 venous plexus of the bladder and of the rectum. 



Symptoms. The young parasites appear to do no injury; in fact, 

 even the adult worms seem to be inoffensive in themselves. The eggs, 

 on the other hand, armed with a sharp point, are the exciting cause 

 of the disease. The position of the parasite in the venous system, and 



Fig. 206.— The bovine 

 blood fluke {Schisto- 

 soma 6oms), male and 

 female. X 9. (After 

 Leuckart, 1894, p. 

 467, Fig. 204 A.) 



Fig. 207. — Cross section of bovine blood fluke 

 (Scliistosoma bovis), showing the position of 

 the feinale in the gynffioophoric canal. X 200. 

 (After Leuckart, 1894, p. 472, Fig. 209.) 



the consequent location of the agglomeration of eggs, determine the 

 particular symptoms. Either the genito-urinary system is attacked, 

 in which case hsematuria is one of the first symptoms, or the large in- 

 testine is attacked and blood is noticed in the faeces. 



If the parasites are lodged in the venous plexus of the genito-urinary 

 system, the chief symptoms are : hjeniaturia, pains in the lumbar region, 

 the left iliac fossa, the thigh, or in the vulva, which may be spontaneous 

 or may accompany micturition ; cystitis, vesical calculus, urinary fistulse, 

 vaginal verminous tumours, nephritis. 



The eggs accumulate in the capillaries, which they rupture ; they 

 traverse the mucosa and fall into the bladder, thus causing more or 

 less hEemorrhage ; in this way the hcematuria is established, which is 



