PLATYHELMINTHES 169 



pain which accompanies micturation. If the parasites are contained 

 in the veins of the rectum, there are similar lesions in this organ; the 

 feces may be stained with blood, and there is a condition somewhat re- 

 sembling piles. 



Diagnosis is best made by a microscopic examination of the urine 

 to determine the presence of the eggs which may be readily recognized 

 by their characteristic elongate shape and polar termination in a sharp 

 point. 



As the lesions are produced by the eggs, the severity of the symptoms 

 will essentially depend upon the number of parasites present. In the 

 majority of cases the infection is light and may give rise to no more than 

 a slight chronic cystitis. In the more rare cases of severe infection death 

 may ensue from rupture of the bladder or from uraemia accompanying 

 an acute nephritis. A heavy intestinal infection may bring about an 

 exhausting and fatal dysentery. 



It is probable that infection has its source in contaminated drinking 

 water. Therefore, where bilharziosis has made its appearance, the water 

 should, as a preventive measure, be filtered, or the cattle removed to an 

 uncontaminated supply. 



Treatment can only be applied to the relief of s}Tnptoms as they 

 appear. 



Class II. Cestoda 



Platyhelminthes (p. 156). — An important character of the cestodes 

 is that, as a result of their advanced parasitism, they have lost the last 

 trace of an alimentary canal, and obtain their nourishment by absorp- 

 tion through their integument of the partly digested food of the host. 

 Also markedly distinguishing them are the two developmental stages, — 

 the bladder worm (Fig. 112, b and c) and the mature worm (Fig. 107) 

 with its sexually developed segments, the first living usually in tissues, 

 such as muscular, Hver, nervous, and serous, of the intermediate host; 

 the second in the alimentary tract of the definitive host. The adult is, 

 in its general form, band-like, and consists of two parts, — the scolex 

 (Fig. 109), which is generally referred to as the head, and a series of 

 segments which are formed from the scolex asexually by longitudinal 

 growth and transverse segmentation. It is due to this fact that an 

 animal is not rid of its tapeworm so long as the head is retained in the 

 intestine. As the segments are pushed on by the formation of younger 

 segments at the scolex, they become progressively wider and longer, 

 the width of the younger ones usually much exceeding their length, 

 while the oldest, which are those most distant from the scolex, may 

 become longer than wide. Each mature segment is hermaphroditic, 

 the uterus usually containing a large number of eggs. In the Tseniidse 

 the genital pores (sexual openings) are on the margin or miargins of the 



