1869.] BOTANY AND ZOOLOGY. 241 



The Shepherdia is a small shrub common in Lower Canada, and 

 was named after Mr. John Shepherd, a former curator of the 

 Liverpool Botanic Garden. J. F. W. 



Tnr Colours of Foliage. — The green colour of leaves, 

 one element of which must be a vegetable blue, has led an 

 American experimentalist to the conclusion that leaves turn red 

 at the end of the season through the action of an acid, and that 

 the green colour could be restored by the action of an alkali. 

 The conclusion has been verified, the Athenoeum declares, by 

 experiment. Autumnal leaves placed under a receiver with 

 vapour of ammonia in nearly every instance lost the red colour 

 and renewed their green. In some, such as the sassafras, 

 blackberry, and maple, the change was rapid, and could be 

 watched by the eye, while others, particularly certain oaks, 

 turned gradually brown, without showing any appearance of 

 green. 



Birds op the Guano Islands. — We copy the following 

 extract, descriptive of " Life on a Guano Island," from a late 

 number of the New York Times. " Among the chief objects of 

 interest to a visitor on Baker's Island are the birds, and they are 

 well worthy of study. During the first night of my stay on this 

 forlorn spot it seemed at times as if the houses were besieged by 

 innumerable tom-cats; then the tumult resembled the sup- 

 pressed bleating of goats, and I heard noises as of bats grinding 

 their teeth in rage ; again it was the querulous cooing of doves ; 

 and soon the chorus was strengthened by unearthly screams, as of 

 ghouls and demons in mortal agony. But on going forth 

 into the darkness to learn the cause of this infernal serenade, all 

 was apparently calm and serene, and the radiant constellation 

 of the Southern Cross, with the neighbouring clouds of Magellan, 

 looked me peacefully in the face, while from another quarter 

 of the heavens the Pleiads shed their " sweet influence'' over the 

 scene. The most quiet time of night with the birds is about 

 daybreak, when they seem to subside into "cat-naps," preparatory 

 to the labours of the day. By day many of the birds range 

 on tireless wing over leagues of ocean in quest of fish. But still 

 the number of those that remain about the island is so great as to 



