DISTOMUM HEPATICUM. 271 



the winter, by their eating the small species passing their winter 

 sleep in their closed shells or the shell-less slugs adhering to roots 

 protected from frost in warm cavities or cellars. Whether the 

 production of D. hepaticum in the human liver may take place by 

 drinking impure water, must remain quite undecided. The find- 

 ing of a young Distomum in the sole of a woman's foot appears 

 to be in favour of an immigration, and a mode of existence 

 similar to the Cercariae. 



For the benefit of those who may wish to trace the mode 

 of production of D. hepaticum more closely by experiment, I 

 may remark that De la Valette found no trematode brood in 

 Limn&us auricularis, Planorbis carinatus, Cyclas cornea, Succinea 

 amphibia, Helix pomatia, Limax agrestis, Anodonta anatina, My- 

 tilus polymorphic, and in the bivalve mollusca about Heligoland ; 

 but met with them in Paludina vivipara, P. impura, Limnaus 

 stagnalis, and Planorbis corneus. 



1 b. Distomum hepaticum, juvenile, immaturum sub cute humana. 



In No. 45 of the ' Mittheilungen der Naturforschenden Gesell- 

 schaft in Zurich/ 1850, Bd. ii, pp. 89 et seq., Giesker and Frey 

 report that the former was consulted, on the 20th December, 1848, 

 about the wife of an overseer in a silk-factory near Zurich. Since 

 the middle of August, a surgeon had been treating this woman 

 for an inflammation in the middle of the sole of the right foot. 

 A somewhat elevated swelling, usually about 1 1J" in diameter, 

 had made its appearance, sometimes towards the outer, sometimes 

 towards the inner edge of the foot, and this, without ever breaking, 

 usually disappeared again in six to eight days. Nevertheless, the 

 middle of the sole always continued somewhat swollen and pain- 

 ful, so that the woman could only tread upon the point of the 

 foot, and was hindered in her occupations. All attempts to 

 cause the separation or breaking of the tumour were vain. 

 In December, 1848, the sole of the foot presented a pale-red 

 swelling, which extended from the inner side of the calcaneus 

 obliquely outwards to the metatarsal bone of the little toe, but 

 which could not be in connection with the bones, the periosteum, 

 or the muscles of the sole of the foot, as the toes were perfectly 

 moveable. It was situated rather in the areolar tissue, beneath 

 the fascia plantaris, was not painful to the touch, yielded longitu- 

 dinally, and appeared to belong to a deep-seated hollow passage. 



