THE ROBIN. 159 



the effect of hunger being increased perhaps by the cold, 

 as the thermometer was about sixty degrees. 



The other bird, still vigorous, he put in a warmer place, 

 and increased its food, giving it the third day fifteen worms, 

 on the fourth day twenty-four, on the fifth twenty-five, on 

 the sixtli thirty, and on tlie seventh thirty-one worms. They 

 seemed insufficient, and the bird appeared to be losing 

 plumpness and weight. He began to weigli both the birdj 

 and its food, and the results were given in a tabular form. 

 On the fifteenth day, he tried a small quantity of raw meat, 

 and, finding it readily eaten, increased it gradually, to the 

 exclusion of worms. With it the bird ate a large quantity 

 of earth and gravel, and drank freely after eating. By the 

 table, it appears that though the food was increased to forty 

 worms, weigliing twenty pennyweights, on the eleventh day 

 the weight of the bird rather fell off; and it was not until 

 the fourteenth day, when he ate sixty-eight worms, or thirty- 

 four pennyweights, tliat he began to increase. On this day, 

 tlie weight of the bird was twenty-four pennyweights : he 

 therefore ate fortj^-one per cent more than his own weight 

 in twelve hours, weighing after it twenty-nine pennyweights, 

 or fifteen per cent less than the food he had eaten in that 

 time. The length of these worms, if laid end to end, would 

 be about fourteen feet, or ten times the length of the intes- 

 tines. 



To meet the objection, that the earthworm contains but a 

 small quantity of nutritious matter, on the twenty-seventh 

 day he was fed exclusively on clear beef, in quantity twenty- 

 seven pennyweights. At night, the bird weighed fifty-two 

 pennyweights, but little more than twice the amount of flesh 

 consumed during the day, not taking into account the water 

 and earth swallowed. This presents a wonderful contrast 

 with the amount of food required by the cold-blooded ver- 

 tebrates, fishes, and reptiles, many of which can live for 

 months without food, and also with that required by 

 mammalia. Man, at this rate, would eat about seventy 



