1893. NOTES AND.COMMENTS. 163 
in the evolution of part ofa vertebrate skeleton is thus to be explained 
on purely mechanical principles. 
To the discussion of this subject another interesting contribution 
has just been made by Professor Cope, who describes two cases of a 
repaired elbow-joint, one in a man the other in a horse (Proc. Amer. 
Phil. Soc., vol. xxx., pp. 285-290, pl. ix.).. In his well-known work 
on “ Animal Mechanism,” Marey has already described instances of 
the natural healing and repair of diseased or dislocated joints—how 
a new articulation is often completely formed, not only with accu- 
rately fitting faces, but also provided with the requisite ligaments 
and synovial fluid. Professor Cope’s paper thus deals merely with 
the details of two remarkable examples of this repair, in which a new 
elbow-joint was completely formed after a dislocation. As the author 
remarks, if the mechanical necessities of a case of this kind lead to 
the production of a completely new and finished joint within the 
space of a few months, ‘‘ how much more easy has it been for stimuli 
of allied character to develop the features of normal articulations 
during the ages of geologic time.” 
‘‘We have here, also,” says Professor Cope, ‘‘an instructive 
lesson as to the matter of inheritance. Everyone knows that mutila- 
tions, luxations, &c., are not usually inherited. This is because they 
are not ‘acquired,’ in the proper sense of the word. Since characters, 
truly acquired, are inherited, it is evident that a long continuance of 
the stimulating cause is necessary to produce a true acquisition. 
The difference between a character produced by causes apart from 
the normal life of an animal, and not repeated, and those produced 
by causes operating daily and hourly for geologic ages, is necessarily 
very great.” 
A GLIMPSE OF THE TROPICS. 
In the recent December and January numbers of the Botanical 
Gazette, Mr. D. H. Campbell gives an account of a six weeks’ vacation 
spent last summer in the Hawaiian Islands. In position, these islands 
are unique, being ‘‘more isolated than any other land of equal area 
upon the globe.” They are 2,350 miles from the nearest part of the 
American mainland, the bay of San Francisco, and about the same 
distance from the Marquesas and Samoa Islands to the south, and 
the Aleutian Islands a little west of north. As Wallace remarks in 
his Island Life, they are ‘‘ wonderfully isolated in mid-ocean,” the 
nearest of the widely-scattered coral reefs and atolls being six or 
seven hundred miles distant, and all nearly destitute of animal or 
plant life. ! 
The group consists of seven large inhabited islands and a few 
rocky islets, extending ina S.E. direction just within the tropic of 
Cancer. Hawaii, by far the largest and most southerly, is 70 miles 
across and about the size and shape of Devonshire; the greater part 
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