PHYSIOLOGICAL 275 



again, after being frozen far harder than glacial ice? Is living 

 necessarily continuous, or can it stop, like a jarred watch, and begin 

 again? Whoever puts the question rightly will be on the way to an 

 answer. 



The "Advance of Science" is a phrase often on our lips, but the 

 persistence of error is seldom referred to, for we are optimists with 

 ourselves. One of the hardy perennials is the belief in the revivi- 

 fication of "mumm}^" wheat, and we read the other day in one of' 

 our leading newspapers that a farmer in Bathurst (N.S.W.) had/ 

 raised a vigorous seven-eared crop from grains which had lain 

 embalmed in Egypt for over 4,000 years. No doubt there are seeds 

 that may retain their vitality for fourscore years or more, but 

 every carefully investigated case of the alleged germination of  

 mummy wheat has broken down. In most cases it turns out that the _ 

 alleged mummy wheat was faked. True mummy wheat is always \ 

 dead. 



THE QUEST OF FOOD 



It is interesting and educative to make a list of all the many 

 different solutions that animals have found for the bread-and- 

 butter problem. Here is our latest attempt, (i) An animal may 

 devour a plant, as the cow the grass. (2) An animal may eat 

 what a plant has made without harming the plant, as a bee the 

 nectar. (3) A green animal may feed like a plant, utilising the sun's 

 rays in photosynthesis; and it may be (a) green in its own right, 

 like the green Bell animalcule, or (b) green, because of partner algse, 

 like the green freshwater sponge. (4) An animal may feed on 

 another living animal, as a tiger on an antelope. (5) An animal 

 may feed on dead flesh, like a carrion beetle. (6) An animal may 

 live on rotten organic matter, prepared for it by bacteria, as is 

 the case with many threadworms or nematodes. (7) An animal 

 may feed on organic debris, or crumbs, as the earthworms on 

 parts of plants lying on the ground. (8) An animal may depend 

 on microscopic animals and plants in the surrounding water, like 

 so many plankton-eating creatures of the open sea. (9) An animal 

 may thrive through its partnership with another animal, whether 

 an internal sjmibiosis (as in 3 {b)) or an external partnership like 

 that between certain hermit-crabs and certain sea-anemones. 

 (10) An animal may be an external parasite, cleaning up the sur- 

 face of its host's skin, as in the case of lice and some mites. (11) An 

 animal may be an internal parasite, living {a) on the digested 

 food in the alimentary canal of its host, e.g. tapeworm; or living 

 {b) on the actual tissue of its host, e.g. liver-fluke on the blood of 

 the sheep's liver. (12) An animal may be a predatory animal from 

 within — surely not strictly to be called a parasite — ^like the ich- 

 neumon grubs devouring the caterpillar. 



