Respiration in Invertebrate Animals. 347 



complexity of the fluids. The figure expressive of its amount 

 progresses upwards with the zoological standard of the organism. 

 This principle explains the faculty conferred upon the Entozoon, 

 by a Nature exhaustless in expedients, illimitable in resources, by 

 which it is enabled to extract oxygen enough for its wants from 

 the least oxygenated of the animal fluids — venous blood — and 

 securely to breathe amid the pestilential atmosphere of the colonic 

 intestine. 



These parasites are capable of sustaining life in any and every 

 recess of the animal body. This fact proves inferentially what 

 the physiologist cannot reduce to positive demonstration, that 

 ever\^ part, every fluid, whether in or out of the vessels, is per- 

 vaded by the electric presence of oxygen. It proves that the 

 respiratory process is really an inseparable attendant on, and an 

 integral and essential part of, the nutritive actions of the body — 

 that it is ubiquitous, not partial — that it vivifies every constituent 

 atom, fluid, and solid of the entire organism*. 



* In order to facilitate the repetition of the observations upon which the 

 general conclusions stated in the text are founded, the author appends here 

 a short hst giving the name and place of abode of the most familiar Nema- 

 toid Entozoa :^- 



Name. Habitat. 



Ascaris megalocephala (Cloquet) ... Intestines of the Horse. 



lumbricoides Small intestines — Man. 



Salaris (Blanchard) In intestines of several fishes. 



Filaria equina {R\ido\i}hi) Folds of the peritoneum of the 



Horse. 



a/fenuof a (Blanchard) Air-cells of carnivorous birds. 



Spiroptera sanguinolenta (Rudolphi) Stomach of Dog and Wolf. 



Spirura Ta?p« (Blanchard) Stomach and intestines of the Mole. 



Megastoma (Rudolpla) Stomach of Horse. 



Oxyuris vermicularis (Dujaidin) ... Rectum — Man. 



Sclerostoma Equinum {Rudo\])hi) ... Caecum of Horse. 



CucM//anM5 Perc« (Miiller) Pyloric appendages of common 



Perch. 



Angiostoma entomelas (Duiardin) ... Lungs of Reptiles. 



Cyathostoma lari {BlsLUch&rd) Orbital cavity of Sea-GuU. 



Strongylus Gigas (Rud. & Miiller)... Kidneys of Horse, Dog, and Man. 



Trichostoma cerophilum (Rudolphi) . Trachea of Fox. 



Trichocepkalus Ao/nini.s (Rudolphi)... Caecum of Man. 



The order Nematoidea, Ccelelmintha (Owen), includes the principal in- 

 ternal parasites of the human subject, viz. Trichina spiralis, Filaria medi- 

 nensis (Guinea worm), Filaria oculi, Spiroptera kominis, Filaria bronchialis, 

 Trichocepkalus dispar, Strongylus Gigas, Ascaris lumbricoides, and Ascaris 

 vermicularis. The Entozoa found in the blood have been recently described 

 under the class-name of Hcematozoa. Several species of Filaria, Monosto- 

 mata, Distomata, and Infusoria, have been discovered in the blood of frogs, 

 dogs, fishes, and mollusca (Micr. Journal, Oct. 1st, 1853). 



24* 



