PLANTS AND ANIMALS. 5 



animals that live in water fast fixed to a given spot. Again, it was 

 imagined that plants might be distinguished from animals by their 

 possessing only at certain times the parts which serve for the main- 

 tenance of the species. But all animals have not organs of propa- 

 gation during the whole of their existence : insects acquire them 

 only in the latest period of their lives, like plants that only flower 

 once. It is true that Anatomy points out the rudiments of these 

 future organs in the Larvae of Insects : but this does not prevent 

 the Larvas of Insects from being termed, in a certain sense, sex-less. 

 Moreover many plants and animals are propagated only by spon- 

 taneous fission, or by buds, without possessing proper parts sub- 

 servient to propagation. To me the difference of Nutrition appears 

 of more importance. It has been observed that Plants live on inor- 

 ganic matters, Animals, on the other hand, on organic. Some 

 animals, it is true, seem to live on earth. SCHWAMMERDAM believes 

 mud to be the nutrient matter of the worm or larva of the Ephemera, 

 and never found any other food in its intestinal canal. PALLAS could 

 find nothing but fine sand in the intestine of Thalassema echiurus. 

 I might allege several other examples, but will only add that man 

 himself sometimes lives upon earth. At least the celebrated HUM- 

 BOLDT tells of a people on the banks of the Oronoco and Meta that, 

 when the waters are low, live upon fish and turtle : but as soon 

 as the streams begin to swell and fishing to become laborious, 

 devour, during a season which lasts for two or three months, enor- 

 mous quantities of earth. The earth which these people eat is a 

 fat soft clay, which they knead into lumps and burn on the outside 

 at a slow fire, and again moisten when required for use. This 

 observation however, now that microscopic investigation has dis- 

 covered in different deposits and kinds of earth entire strata of 

 living or fossil organic beings, admits of another explanation 1 . 

 That earth may have contained organic constituents, as was the 

 case with the earth that, mixed with meal and leaves of trees, was 

 baked for bread on the failure of the crops in the year 1832 in the 

 north of SJcandinavta, and in which RETZIUS discovered nineteen 

 different forms of Infusories, or rather of the fossil remains of these 

 animals. In the same way, the mud and sand, found in the intes- 



1 Comp. EHRENBERG, Das unsicTiibar wirJcende organiscJie Lebcn. Leipzig, 1842. 

 pp. 41, 42. 



