ON BIOLOGY. 69 



on the part of Nature, the operations of which are still 

 but imperfectly known to the biologist, and to these we 

 can but barely allude. There are the several phases of 

 the general law of correlations, as exemplified in many 

 ways both on the part of animals and of plants; of the 

 laws of the relations existing between organisms, on the 

 one hand, and all that goes to the make-up climate on the 

 other; of the laws of protective resemblances among 

 animals and plants; of parthenogenesis and other peculiar 

 forms of reproduction; of the laws of variation, and the 

 effects of use and disuse of organs; of the laws of the ex- 

 tinction of species, and of persistent types of animals; and 

 some few others which show those delicate compensations, 

 equilibriums and balancings that are ever in operation 

 throughout all Nature and of which we yet ha,ve so very 

 imperfect a knowledge. Still, to some extent, we have 

 been enabled to arrange and classify those laws, and these 

 classifications will become more perfecc as the examples 

 they present become better understood. Upon every 

 hand, however, cause and effect are seen to be un- 

 ceasingly in action, and ever with an absolutely unvary- 

 ing exactitude whatever may be the nature or class of 

 cases wherein it is seen. The balancements are sustained 

 everywhere with a precision admitting of no variation 

 whatever; all cells moving in harmony at all instants of 

 time, and in obedience to uncompromising laws. No field 

 could be more inviting to the biologist for his investi- 

 gations and his meditations, as a few examples which I 

 select from various biological authorities will go far 

 toward showing. 



A number of years ago I had under my observation a 

 man that possessed six fingers upon either hand, and he 

 had several sisters and a brother exhibiting the same 

 monstrosity. In some of the cases, however, but one 

 hand showed it; and a brother in the family had normal 

 hands. Only one of this man's parents, his father, I 

 think, showed the condition, and in all the number of 

 toes on the feet were normal. In such 

 cases the numeral relation of the toes and 

 fingers vary, but if a six-fingered and six-toed man should 

 marry a woman exhibiting the same digital characters, 

 and propagation were to be kept up for generations by 

 puropinbreeding the character would become perma- 

 nently established and result in a special race of such peo- 

 ple. Haeckel says: "In a Spanish family, each child ex- 

 cept the youngest had the number six on both hands and 

 feet; the youngest, only, had the usual number on both 



