216 SCIENCE PROGRESS 



It must not be forgotten, however, that Thayer's work is 

 mainly inductive. What has been said above is necessarily 

 more crudely expressed and more dogmatically asserted than 

 would commend itself to the author of Concealing Coloration. 

 What gives its rare note of originality and freshness to the 

 book is the mass of records of first-hand observations and 

 experiences with which it is filled. Thayer's may not be the 

 only theories which could be deduced from his facts but at 

 any rate there can be no doubt of the interest and value of 

 those facts. Take the account he gives how he wrestled with an 

 unbelieving visitor to his house at Monadnock, New Hampshire. 

 This man had rashly asserted that the American coral snake, 

 with its red, black and gold rings, was actually the most con- 

 spicuous object in nature. Thayer, with his creed that " there 

 is no such thing as complete intrinsic conspicuousness," was of 

 course pledged to undeceive him. So he made four imitation 

 snakes, one black, one scarlet, one gold and one good facsimile 

 of a coral snake — scarlet, black and gold in one — and put them 

 all in the grass. He then got the sceptic to look at them at a 

 distance of about four yards, whence he saw them all at once 

 except the coral snake, which he was actually unable to detect at 

 his feet. It is to be hoped that he became at once a convert to 

 the efficacy of " countershading " and to the obliterative value of 

 " secant markings." 



Here again is a record taken from Thayer's journal, as quoted 

 in his book, of a similar conversion, in which case, however, 

 Thayer was the convert and the place of the prophet was taken 

 by Botanrus lentiginosus, the American bittern. This bird, as is 

 well known, has a curious habit of standing in a reed bed abso- 

 lutely erect with its bill pointing to heaven. This it has always 

 been assumed to do in order to look like a stick or stump such 

 as can occasionally be seen projecting among reeds and thereby 

 to escape recognition as a bird. " If stick mimicry," says Thayer, 

 " were the explanation of the bird's curious trick, what would be 

 the function of the finely-developed sharply-contrasted stripes of 

 light and dark running lengthwise of the head and neck and 

 best shown when the bittern is standing erect with feathers 

 closely depressed ? It is plain that these markings cannot help 

 the ' stick ' aspect but must rather injure it, inasmuch as a single 

 stick or stem would be of uniform coloration or at most mottled 

 rather than marked with sharp and strong longitudinal stripes. 



