858 ON WORM PARASITES. 



From the repoi^ts of Dr. Becldard and Dr. Leiper I gather that 

 during the same period 41 additional cases of infection with tape- 

 worms, and 53 of infection with Nematodes have been observed. 

 To these must be added a very considerable number of infections 

 with larval Filarise observed by Mr. Plimmer. These figures, 

 excluding the larval Filarise, give a total of about 180, of which 

 the infection with Trematodes, Cestodes, and Nematodes is 

 respectively 28, 56, and 113. Tliis appears to show that 

 Trematode parasites are much rarer than other forms, but that 

 is certainly not the case. It must be remembered that only a 

 comparatively small number of the animals passing through the 

 Prosectoi'ium were adequately searched for Trematodes. The 

 extent to which Trematodes and the smaller intestinal Nematodes 

 escape notice except when thoroughly searched for may be 

 gathered from the following table. 



Trematodes. Cestodes. Nematodes. 

 Total number of cases of infection 28 56 113 



Number of cases found only on 



further examination 20 15 60 



Percentage 71 26 53 



It may be added that the bulk of the Cestoda which were 

 not noted on first examination were small immature forms or 

 fragments of no value. It may therefore be safely affirmed that 

 only a negligible fraction of the mature tapeworms actually 

 escape detection in the Prosectorium. The matter, however, is 

 different with Trematodes ; and in view of the fact that only about 

 one-tenth of the total number of animals dying in the Gardens 

 have been submitted to a thorough examination, it must appear 

 that the number of Trema.todes actually occurring is considerably 

 greater. Even allowing that they only occur in 5 per cent, of 

 cases, which is taking an extremely low estimate, we ought to 

 have had instead of 28 records a total of well over 100. In the 

 same way the number of small intestinal Nematodes ought to 

 be much increased. 



These remarks, however, are not intended as a criticism of the 

 efforts of the prosectorial staff. Parasitic worms are, after all, 

 only a very small part of the work of this department of the 

 Society, and as I have mentioned in the beginning of this com- 

 munication, considerable praise is due for the results actually 

 obtained. My chief intention is to show that parasitic worms 

 are undoubtedly an important concern and that their importance 

 justifies the attention which is being paid to them. Their claim 

 to notice had until recently been somewhat neglected by the 

 Society, and it seems necessary that someone should ofier a plea 

 for their vindication. There can be no doubt that the attention 

 which the Society, thanks to the eflbrts of Dr. Chalmers Mitchell, 

 is devoting to these forms will do much to benefit Zoology as a 

 whole. 



