MISCELLANEOUS PAPERS. 391 



instant, and is there some chemical or physical contact with objects 

 out of which materials are selected for nests ? 



The spider without previous instruction spins a web of mechanical 

 perfection, scaflFolding for the structure, weaving the geometrical figure 

 with mathematical exactness, taking up the groundwork, and if dis- 

 turbed the whole process is repeated. 



The cooperative incubating industry existing among the brush 

 turkeys of Australia {Megapodes) is even more wonderful. Contrary 

 to maternal instinct, these birds gather a great heap of earth and 

 leaves, sometimes fifteen feet high, in which they lay their eggs, and 

 leave them to be hatched by the heat produced by the fermentation 

 and decay of the vegetable matter. The young shift for themselves 

 at once, and may never come in contact with the mother bird. It 

 might be, though it sounds like a fairy tale, that a fortuitous heap 

 was made as a result of the scraping propensity evidenced by the very 

 large shanks of this bird, and, by another fortuitous coincidence, the 

 eggs were left in the said heap and hatched, sending forth a brood 

 congenitally prepared to establish this custom, so that the drudgery of 

 sitting for days on those uninteresting, never-to-be-too-much-sat-upon 

 objects might be foregone. 



To all these and a thousand more, given by Mr. Morgan and others, 

 we must say, when asked why and wherefore, ignorahimus. 



Doctor Loeb has made a valuable contribution in the explanation of 

 reactions in unicellular organisms. How far this theory can be ex- 

 tended with reference to more complex organisms remains for future 

 investigation. 



