AXAEROBIO^SL^ AXD EXDOPARASITISM 283 



anow-Grigoriew and Hoeppli (I.e.) and by Giovannola 

 (1936), the latter working without Imowledge of either 

 Pintner's or Stepanow-Grigoriew and Hoeppli's papers.) 

 But this glycogen increase is not dependent on the mi- 

 gratory process. It has been shown that a comparable 

 polysaccharide accumulation takes place in dog hook- 

 worms when they develop directly within the small in- 

 testine. In order to separate the worms from the lar- 

 vae that had gone through the circuit, a tracheotomized 

 dog was used in which no larva could go over from the 

 trachea to the esophagus (Stepanow-Grigoriew and 

 Hoeppli). It might be remarked too that the larvae of 

 parasitic nematodes are all very small and have, there- 

 fore, a high surface, volume ratio. Since the intestine is 

 usually not completely devoid of oxygen, they should be 

 able to get, before they have gro^vm to larger sizes, rather 

 significant amounts of oxygen. One can hardly conceive 

 that they would die of asphyxiation before the abundant 

 food available in their surroundings would allow the 

 building up of a sufficient amount of reserve material for 

 the transition to a fermentative type of metabolism, 

 even if their original glycogen stores would not be suf- 

 ficient for this purpose. We are thus led, on the basis of 

 these arguments, to reject Pintner's theory. 



As to the parasitic protozoa only one attempt seems to 

 have been made to consider their anaerobic functions as 

 a clue to their ancestry. Lauterborn (1916) pointed out 

 a curious general similarity between the sapropelic pro- 

 tozoan fauna and the rumen- or termite-protozoa, and 

 also between their respective habitats. In the three hab- 

 itats a pronounced cellulose fermentation takes place, 

 the concentration of solutes is relatively high, there is 

 little or no free oxygen present, but a large quantity of 

 carbon dioxide and combustible gases. These common 

 features in the environment may have been responsible 

 for a series of rather pronounced similarities in the or- 



