FREQUENCY OF ITS OCCURRENCE. 541 



from a communication of Hosier's, 1 according to which there were in 

 20,000 swine only 9 markedly infested with bladder-worms (1 : 2222), 

 although every eighth animal harboured a few Cysticerci. It is, 

 indeed, possible that the bladder- worms which were abundantly found 

 in the omentum and viscera did not exclusively belong to Cysticercus 

 cellulosce, but I think, from the results of my experience in Giessen 

 in the year 1860, that we may conclude that there are districts in 

 Germany in which 23 per cent, of the swine are infected with 

 bladder -worms in varying numbers. 



Eeports from Italy tell the same story. Pellizzari estimates the 

 number of specially measly swine at 3-4 among 11,000-12,000 (one for 

 every 3000-4000), while Perroncito 2 reports that, according to the 

 statement of an official inspector (Langueyeurs), one diseased specimen 

 for every 250 occurs in Turin, while in Milan (according to a calculation 

 based upon three months) 80 were found in 5500, or one in seventy. 



However imperfect these statistical results may be, this much is 

 certain, that Cysticercus celluloses in the pig is by no means rare, and, 

 indeed, is far more abundant than Trichina. 3 



This is not only true in regard to the pig, but also, as we have 

 recently learned from the computations of Mtiller 4 and Dressel, 5 for 

 man. The various results are conflicting, even those of the same authors 

 varying when they have observed in different localities, so that we 

 are perhaps justified in believing that the occurrence of the Cysticercus 

 is as much determined by local conditions as is the occurrence of the 

 Tcenia; at all events the reports seem to agree in establishing a 

 diminution in the frequency of the bladder-worm. 



If one calculate from the existing data as contributed by the 

 Pathological Institutes of Berlin (Virchow), Gottingen (Fb'rster), 

 Dresden (Zenker), and Erlangen (Zenker), one finds in a total of 

 9753 post-mortem examinations 127 cases of Cysticercus cellulosce^ 

 or 1*3 per cent. One bladder- worm subject occurs in about seventy- 

 six examinations, a ratio which is more than double that similarly 

 computed for T. solium (p. 531). It is, however, open to question 

 whether we can directly compare these two cases, and conclude that 

 Cysticercus cellulosce is twice as frequent as T. solium. For the results 

 of these examinations do not give one any correct impression as to 

 the numerical frequency of parasites, especially as regards those 

 which occur incidentally, and do not directly call for medical assist- 

 ance. In numerous cases of Cysticercus the trouble is a very serious 

 one, sometimes occasioning death ; but, besides these, there are a 



1 Loc cit., p. 426. 2 loccit., p. 64. 3 See Vol. II. 



4 " Statistik der menschlichen Entozoen." Dissert, inaug., Erlangen, 1874. 

 6 " Zur Statistik des Cysticercus cellulosae." Dissert, inaug., Berlin, 1877. 



