3 io 



THE ANIMAL PARASITES OF MAN 



Each opening is closed by a light-coloure^i plug. ^ The eggs measure 

 0*05 0*054 mm. in length and 0*023 mm. in breadth ; they are 

 deposited before segmentation. Trichocephalus trichiurus usually 

 | / lives in the caecum of human beings and is also occasionally 

 found in the vermiform appendix and in the "colon, excep- 

 tionally also in the small intestine ; usually only a few specimens 

 are present, and these do not cause any particular disturbances, 

 although, as Askanazy found, they feed on blood ; in other cases 

 cerebral symptoms of more or less severity are observed when 

 trichocephali are present in large numbers., At post mortems per- 

 formed soon after death the filiform anterior extremity of the 

 worm is frequently found embedded in the mucous membrane 

 (Askanazy). 



The whip-worm is one of the most common parasites of man and 



appears to be distributed over the entire 

 surface of the globe ; it is, however, 

 more frequent in the warmer regions. 

 It is found in persons of both sexes 

 and all ages with the exception of 

 infants. In autopsies it is found in 

 the following numbers^ In Dresden in 

 2-5 per cent., in Erlangen in in per 

 cent., in Kiel in 31-8 per cent., in 

 Munich in 9-3 per cent., in St. Peters- 

 burg in 0-18 per cent., in Gottingen 

 in 46-1 per cent., in Basle in 23*7 per 

 cent., in Greenwich in 68 per cent., in 

 Dublin in 89 per cent., in Paris in 

 about 50 per cent., and in Southern 

 Italy in almost 100 per cent. On ex- 

 amining the faeces the eggs of the 

 whip-worm were found as follows : In 

 Munich in 8*26 per cent., in Kiel in 

 45 -2 per cent., in Greifswald in 45 per 

 cent., in North Holland in 7 per cent., 

 in Novgorod in 26-4 per cent., in St. 

 Petersburg in 5-0 per cent., in Moscow 

 in 5-3 per cent. 



The development of the eggs is completed in water or in moist 

 soil, and occupies a longer or shorter time according to the 

 season ; the eggs possess great powers of resistance, as do the 

 larvas, which, according to Davaine, may remain as long as five 

 years in the egg-shell without losing their vitality. Leuckart 

 proved by experiment that direct infection with Trichocephalus 

 affinis (ovis aries) and Tr. crenatus (Sus scrofa dom.) was produced 



FIG. 205. Trichocephalus tri- 

 chiurus. On the left male ; on the 

 right female with the anterior ex- 

 tremity embedded in the mucous 

 membrane of the intestine. Below 

 egg. 



