358 FUNGI INHABITING THE ANIMAL BODY. 



in Acldya (§ 247). It is not a little curious, moreover, that the 

 Entozoa or Parasitic Worms infesting the alimentary canal of these 

 animals should be frequently clothed externally with an abundant 

 growth of such Plants : in one instance Dr. Leidy found an Ascaris 

 bearing twenty -three filaments of Enter obry us, "which appeared 

 to cause no inconvenience to the animal, as it moved and wriggled 

 about with all the ordinary activity of the species. " The presence 

 of this kind of Vegetation seems to be related to the peculiar food 

 of the Animals in whose stomachs it is found ; for Dr. Leidy could 

 not discover a trace of these or of any other parasitic Plants 

 in the alimentary canal of the carnivorous Myriapods which he 

 examined ; whilst he met with a constant and most extraordinary 

 profusion of Vegetation (Fig. 170) in the stomach of a herbivorous 

 Beetle, the Passulus cornutus, which lives, like the Iuli, in stumps 

 of old trees, and feeds as they do on decaying wood. Of this vege- 

 tation some parts present themselves in tolerably definite forms, 

 which have been described under various names ; whilst other 

 portions have the indefiniteness of imperfectly-developed organisms, 

 and can scarcely be characterized in the present state of our know- 

 ledge of them. With regard to several forms, indeed, Dr. Leidy 

 expresses a doubt whether they are Parasitic Plants, or whether 

 they are out-growths of the membrane itself. 



267. There are various diseased conditions of the Human Skin 

 and Mucous membranes, in which there is a combination of Fun- 

 goid Vegetation and morbid growth of the Animal tissues : this is 

 the case, for example, with the Tinea favosa, a disease of the 

 scalp, in which yellow crusts are formed that consist almost entirely of 

 the mycelium, receptacles, and sporules of a fungus ; and the like is 

 true also of those white patches (Aphtha) on the lining membrane 

 of the mouth of infants, which are known as Thrush, and of the 

 exudations of ' false membrane' in the disease termed Diphtheria * 

 In these and similar cases, two opinions are entertained as to the 

 relation of the Fungi to the Diseases in which they present them- 

 selves ; some maintaining that their presence is the essential con- 

 dition of these diseases, which originate in the introduction of the 

 Vegetable germs; and others considering their presence to be 

 secondary to some morbid alteration of the parts wherein the 

 fungi appear, which alteration favours their development. The 

 first of these doctrines derives a strong support from the fact, that 

 the diseases in question may be communicated to healthy indi- 

 viduals, through the introduction of the germs of the Fungi by 

 inoculation; whilst the second is rather consistent with general 

 analogy, and especially with what is known of the conditions under 

 which the various kinds of fungoid ' Blights ' develope themselves 

 in or upon growing Plants (§ 270). — It is not a little remarkable 



* Nearly allied to these is the form of Vegetation recently observed on 

 many specimens of imported Hair, and wrongly described as a Grega- 

 riniform parasite. See Dr. Tilbury Fox in " Science Gossip," May, 1867. 



