DEATH AND DEGENERATION OF THE ECHINOCOCCUS. 651 



more and more, loses its former pellucid appearance, and becomes an 

 indiarubber-like substance, which finally (though perhaps after a con- 

 siderable time) degenerates into an amorphous detritus. The tumour, 

 of course, decreases in size as the fluid is absorbed. This may take 

 place so thoroughly that only a small knot remains where there 

 formerly existed a conspicuous Echinococcus. 



Sometimes during this change a large quantity of lime, especially 

 of the carbonate, is deposited in the former granular layer, so that the 

 latter can not only be removed from the substance of the surrounding 

 organ as a connected mass, but even presents considerable resistance 

 to the knife. Berthold examined the calcareous shell of such an 

 Echinococcus from the lung of an old dromedary, and distinguished 

 on section two layers, one over the other. Of these, the outer and 

 firmer was composed mostly of phosphate; the inner, on the other 

 hand, of carbonate of lime. In the latter there were here and there 

 massive deposits of lime of a distinctly crystalline character. 1 



The changes here described have been in part already observed by 

 the older anatomists, though their true nature was not recognised. 2 

 Starting from the supposition that the Echinococci were of the nature 

 of tumours, it was thought that transitions might be traced from the 

 hydatids sometimes into tubercles (Morgagni), sometimes also into 

 atheromata, steatomata, melicerida (Ruysch). Even the demonstration 

 that the Echinococci were animals allied to the bladder-worms has 

 not quite dismissed the old idea, for even in 1819 the attempt was 

 made to deduce from them not only tubercular deposits, but also 

 scirrhus and other neoplastic formations. 3 



It requires no special mention that the many and serious dis- 

 turbances induced by the Echinococcus suggested their association 

 with dangerous tumours ; and that all the more, since the life-history 

 and development of the parasite exhibits various phases, the zoological 

 nature of which is difficult to determine. I recall, for instance, the 

 existence of the so-called " secondary " hydatids, and further, that 

 the power of movement, which was usually regarded as one of the 

 most important attributes of animal life, seemed here wholly absent. 



The medical public has but slowly and reluctantly acknowledged 

 the true nature of this parasite ; and even when no one doubted that 

 the Echinococcus, and particularly the hydatid Echinococcus, was in 



1 GottingiscJie gelehrte Anzeigcn, p. 1975, 1837. 



2 See Kiichenmeister's results, Deutsh. Archiv f. Gesch. d. Med., Bd. ii. u. iii. 



3 Baron, " An Enquiry illustrating the Nature of Tuberculated Accretions and the 

 Origin of Tubercles:" London, 1819; and a subsequent paper, "Illustrations of the 

 Enquiry respecting Tuberculous Diseases : " London, 1822. One must note that Baron 

 used " hydatid " in the wide sense of the old physicians, and made it include more than 

 the Echinococci. 



