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rived : since similar organisms are abundant in every water, there can 

 be no difficulty in supposing that a portion of the substance itself, or 

 some of its reproductive germs or sporules, may have been swallowed 

 by this individual in the water which she drinks. I have made par- 

 ticular enquiry as to her diet, and find that it is of the ordinary de- 

 scription, both animal and vegetable, and that her drink is limited to 

 tea and water, but of the latter she takes very little. The water is 

 supplied by the ordinary service-pipes of the metropolis, and not from 

 any particular well or pump. 



At this point of the enquiry the same difficulty occurs as in the 

 question of the origin of the ordinary internal parasites of animals, 

 the Entozoa. Whence are they derived, and how is their existence 

 in the body to be explained by reference to an external origin, since 

 they are not found in any other situation ? It would be almost impos- 

 sible to conceive that the substance which I have described could be 

 found out of an organized body, for example, in a stream of water ; 

 but I would suggest, that having derived its supplies of nourishment 

 from an organized body (in this case, as may be presumed, from the 

 surface of the intestine), its characters may have been so far modified 

 consisting in fact, as it does, of animal matter, as to render the object 

 no longer recognizible as an already existing species. 



I believe the fact which I have just announced is new to science; 

 I have not myself met with any similar instance, but it belongs to a 

 class of facts which modern microscopic investigation is rapidly ren- 

 dering familiar to all who value that species of observation. In the 

 journals of the day may be found numerous examples of parasitic 

 growth from various parts of the bodies of animals, and even of man. 

 From the surface of the body, as in the confervoid growths attached 

 to the fins and gills of fishes, and cryptogamic vegetation constituting 

 the essential part of certain morbid products, as in the porrigo of the 

 human subject. Other examples are recorded of internal vegetations, 

 Entophyia as well as Entozoa, as from the lungs in birds, and even 

 of the human subject, as recorded by Dr. J. H. Bennett, in a case 

 where such organisms were expectorated by an individual under pul- 

 monary consumption. Mr. Goodsir has related a case in which thou- 

 sands of animals, allied to the genus Gonium, were vomited from the 

 human stomach ; and to the mass of evidence which is thus rapidly 

 accumulating, of parasitic growths, both animal and vegetable, in- 

 festing the bodies of man and animals, I beg to add the details of the 

 analogous formation which I have just had the honor of describing 

 to the Society. 



