INTERPRETATION OF NATURE. 41 
A friend of mine was undertaking some research on a group 
of sponges some years ago. During this work he found it 
necessary to dissolve the spicules in an acid, which at the same 
time stained the thin film of animal matter coating them. 
As the little calcareous rods finally disappeared in solution, a 
black streak made its appearance on the microscope slide. 
My friend deduced from this an axial canal lined with animal 
matter—a common enough thing in the sponge world. It was 
by little more than chance that he eventually arrived at the 
true explanation, ¢.e., that the outer film of animal matter 
was elastic, and the black line left by the spicule when it passed 
away was the contracted film. The spicule had, in fact, no 
axial canal at all. 
Columbus had no ideas of a new continent when he sailed 
westwards, and although he visited the West Indies on four 
occasions, he died in the belief that he had discovered the 
eastern coast of Asia. 
The preconceived idea about evolution often blinds the 
observer to another quite as logical interpretation of the facts. 
To quote an example. You will recall how Lamarck and his 
followers explained the lengthy neck of the giraffe on the 
supposition—since substantiated by evidence—that the early 
giraffes were short-necked, like other creatures, but circum- 
stances necessitated their stretching for food, and the constant 
straining of the neck resulted in the permanent lengthening 
of that member, which, as it chanced to be hereditary, was 
handed down and added to by succeeding generations. 
The followers of Darwin, of course, believed this interpre- 
tation to be wrong, in so far as the starting of the variation 
in length of neck from that of the normal was assumed by 
Lamarck to be due to the mere process of stretching. The 
Darwinians, as we all know, believed that the variation arose 
somehow in the germ cells, from which the longer necked 
giraffes originally sprang. But both the later Lamarckians 
and Darwinians seem to have believed that the long neck of 
the giraffe was a necessary condition of the creature’s existence. 
That if the necks had not been lengthened, the whole 
race of giraffes would have become extinct by reason of 
starvation. 
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