98 TRANSACTIONS OF THE 



A bare enumeration of the many cases cited is all that can be 

 given in this abstract. 



Under the first of those groups the following facts were set down : 

 i. That the longitudinal cohesion of the outer bark of many- 

 trees restricts their natural growth by binding the trunk too tightly 

 and compressing the cells of the cambium layer. So obvious is 

 this that horticulturists successfully relieve them by artificially slit- 

 ting the bark. 



2. That many plants bloom during a period of mild weather in 

 autumn or winter, when there is no possibility that their fruit can 

 reach maturity. 



3. That the sting of many insects is so strongly barbed that it 

 cannot be withdrawn from the body stung, but instead is extracted 

 from that of the insect along with the viscera to which it is attached, 

 resulting in the death of the latter. As only females are provided 

 with stings the destruction of so many of that sex must be a disad- 

 vantage to the species. 



4. That female opossums having only thirteen teats have been 

 known to give birth to fifteen or sixteen young, and, as the con- 

 tinued life of each embryo depends upon its permanent attachment 

 to a teat, the excess over the number of the latter must necessarily 

 perish. 



5. That moths, beetles, ephemerae, and other insects possess a 

 suicidal propensity to fly into a flame. 



6. That birds and animals on newly discovered islands have no 

 innate fear of man, and allow themselves to be readily caught, so 

 that they are soon exterminated. 



7. That animals attacked with rabies immediately acquire a dis- 

 position to bite others, whereby the deadly malady is multiplied. 



8. That many imperfectly integrated annelids labor under a 

 great disadvantage from being obliged to support a multitude of 

 similar organs in different somites. 



While none of the above facts are capable of a teleological, or 

 optimistic explanation, it was shown in each case that from the 

 point of view of evolution they may all be readily accounted for. 



