64 INTRODUCTION TO CRTPTOGAMIC BOTANY. 



instances the overwhelming shade is quite sufficient explanation 

 of the dormant seeds and tubers, and the other cases would 

 admit probably of as easy a solution, were they studied on the 

 spot. Now as regards Fungi and the lower Algse, it cannot 

 be denied that their appearance is often puzzling enough, but 

 as much of the mystery which was formerly attached to the 

 phenomena exhibited by intestinal worms has vanished under 

 the investigations of Steinstrupp, Siebold, Van Beneden,t &c., 

 I doubt not that those facts which still appear so perplexing, 

 will admit some day of easy explanation. Wherever proper 

 pains have been taken to exclude every possible source of error, 

 no moulds or animalcules have ever made their appearance, 

 without the possibility of the access of previous spores. 

 After prolonged boiling and exclusion of the external air, as 

 capable of conveying spores, or its admission only after first 

 traversing some fluid, as sulphuric acid, which is destructive 

 of life both in the animal and vegetable world, and therefore 

 would char any spore that the air might contain, not a Hving 

 molecule has ever originated in any organic substance or fluid 

 charged with organic matter. And the same may be said of 

 reputed metamorphoses of Algse into Fungi, and the contrary ; 

 both notions rest either on imperfect observations, incomplete 



they come to maturity. A recent memoir of Fabre, in Annales des 

 Sc. Nat., relative to the development of the tubers in Orchis hircina, 

 may suggest some hints on this subject. Ann. d. Sc. Nat. S6r. 4, 

 vol. 4. 



t I allude more especially to the origin of flukes, tapeworms, &c., 

 from minute creatures nursed in the bodies of other animals. The con- 

 nection between the Cystocercus of the pig and Tcenia Solium the 

 common human tapeworm ; that of cysts in the heads of sheep and the 

 tapeworm of the dog ; a parasite of Lymnma and the sheep fluke, are 

 now established beyond doubt, and these are not the only examples. 

 It would be curious to ascertain of what worm the sorices of the human 

 liver are the infant condition. That the animals hatched from the ova 

 of the tapeworm should be able, notwithstanding the powerful jaws 

 with which they are furnished, to travel, in spite of all impediments, as 

 far as the brain, even though it be by penetrating the blood vessels, is 

 perfectly astonishing. It is easier to estimate the progress of such 

 species as are nursed in the liver, by way of the hepatic duct. 



