16 ANIMAL PARASITES. 



very well known to Plater, as also in the latter to Bartholin 

 (' Hist. Anat. rar./ sect, ii, obs. 67) as early as 1653, and in Plater's 

 time even to the butchers as something very common. Bartholin 

 (1. c, obs. 49) was aware of their occurrence in goats ; and lastly 

 Steno (' Act. Barthol. med./ i, p. 135), and Harder (' Apiai.' obs. 

 3), recognised their occurrence in Ruminants almost as a matter of 

 course. Besides the above-mentioned cases, others of Echinococcus 

 hominis (nutricipariens, Kuch.) are also known as occurring at this 

 period, namely, that of Riverus (Bonetus, 1. c, lib. iii, sect. 21, p. 

 1505), in which, after the opening of an abscess in the liver, more 

 than 200 vesicles fell out, and a cure followed ; that of Joachim 

 Camcrarius (' ibid./ p. 1532), in which, after the abscess was opened 

 below the processus ensiformis, an immense number of vesicles, 

 of the size of hens' and pigeons' eggs and smallex', passed out, and 

 the patient lived for a year. Pallas (' Neue Nord. Beitr./ 

 i, p. 84) also subsequently reported a case of Echinococcus hominis. 

 Even at this early period it was known that the hydatids, as they 

 were called, presented certain pecularities. Bartholin speaks 

 of a "substantia flava in the interior of the vesicle/' Steno of a 

 " grisea qusedam materies pisi mole" (by which, in both cases, 

 the head retracted into the sheath is indicated), and Harder lastly 

 mentions " Hydatides in duplicatura omenti libere fluctuantes/' 

 and also of those which adhere to the neighbouring parts of the 

 body by cellular tissue and blood-vessels ; but, as already observed, 

 the animal nature of these hydatids remained entirely unknown 

 until the years 1684 and 1685. 



In 1684, Redi first united these hydatids with other encysted 

 animal parasites, as " glaudulette o vesichette verminose," and 

 mentions (' Opere di Redi,' Yenezia, i, p. 21), as examples of 

 such worm-sacs, a Cysticercus of the marten {Cyst, cordatus? 

 Leuck.), and at p. 110, the Cysticercus pisiformis of the rabbit. 

 Redi's " lumbrichetto" is the retracted neck of the C. cordatus; 

 but in C. pisiformis he distinctly recognised the connection of 

 the "lumbrichetto" (from the time of Pliny "lumbrici" was the 

 common denomination of all intestinal worms) with the caudal 

 vesicle. Redi, indeed, gives no further reasons for the animal 

 nature of these hydatids, but speaks of the independent move- 

 ments of these animals, and regards them as probably the 

 embryos of the Distoma found in the liver of the rabbit. Appa- 

 rently, independently of Redi, the surgeon Hartmann, of Konigs- 

 berg (-'Misc. cur. seu Ephem. Acad. Nat. Cur.,' decur. ii, aim. 



