May 2, 1902.] 



SCIENCE. 



715 



pear.' If this refers to the commoii Missouri 

 cactus, would it not be well to follow the Mexi- 

 can in making it a useful food for cattle and 

 sheep, by cutting the plant to the ground, and 

 throwing it on piles of dry brush, which are 

 fired, and the spines scorched off, when it is 

 greatly relished by the stock. 



Charles H. STERNBEEa. 

 Lawkence, Kansas. 



the song of birds. 



To THE Editor of Science: Some time ago 

 Mr. W. E. D. Scott contributed to Science an 

 article upon the song of birds, drawing the 

 conclusion that when isolated from their kind 

 birds would originate a song. 



In the building in which my office is located 

 there is a canary that was taken from its par- 

 ent bird when quite young, and grew to adult 

 age entirely isolated from other birds. It has 

 developed a song of its own made up, as nearly 

 as I can distinguish, of but three tones sung 

 as a phrase of seven notes. While the song 

 suggests that of the ordinary canary it is not, 

 I would say, actually any part of it; it is 

 sometimes used singly, though generally re- 

 peated several times, and there is little if any 

 variation from the original phrase or form. 

 Walter S. Kelley. 



THE conger eel. 



To the Editor of Science : The TI. S. Na- 

 tional Musexim has recently received from the 

 New Tork Aquarium a specimen of the larval 

 form of the conger eel, which was captured in 

 Gravesend Bay, N. Y. It measures four 

 inches in length and is in a good state of pre- 

 servation. Another specimen recently sent to 

 the Aquarium was taken on the New Jersey 

 coast. 



Although the adult conger eel is common in 

 New York waters, the Leptocephalus form has 

 been recorded but rarely. Brevoort recorded 

 its occurrence in the vicinity of New York 

 City many years ago. 



Barton A. Bean. 



U. S. National Museum, 



Washington, D. C, 



April 2.5, 1902. 



correspondence of the late professor leidy. 



To the Editor of Science : The undersigned 

 has been collecting for some time the corre- 

 spondence of the late Professor Joseph Leidy. 

 Before the same is published, he would be 

 indebted for any such which may be in the 

 possession of the readers of Science. Care 

 will be taken to return the originals if re- 

 quested. Kindly address. 



Dr. Joseph Leidy. 

 1319 Locust Street, 



Philadelphia, Pa., 

 April 21, 1902. 



SHORTER ARTICLES. 



THE hydrolysis AND SYNTHESIS OP ETHYL 



butyrate by platinum black. 



Kastle and Lowenhart have shown that the 

 catalytic action of the enzyme lipase is revers- 

 ible, i. e., that it accelerates not only hydrolysis 

 of fats into fatty acid and alcohol, but also the 

 synthesis of fats from fatty acids and alcohol 

 (Chemical News, February 8, 1901-March 15, 

 1901). 



In an investigation on the action of enzymes 

 which I began over a year ago at the suggestion 

 of Professor Loeb, it occurred to us to try ex- 

 periments with platinum black as the active 

 principle in place of lipase. 



I found that platinum black acts quite com- 

 parably to lipase. Platinum black hydrolyzes 

 ethyl butyrate as well as synthesizes it from 

 butyric acid and ethyl alcohol. 



In, my experiments the following chief facts 

 were found : 



1. Platinum black hydrolyzes ethyl butyrate, 

 as is shown by the constant and definite in- 

 crease in the acidity of the solution. 



2. The velocity of the action is a function of 

 temperature, i. e., an increase in temperature 

 from 0°C. to 40° C. is accompanied by a corre- 

 spondingly increased hydrolysis. 



3. The velocity of the reaction is a function 

 of the quantity of the platinum black used ; but 

 independent of the quantity of ethyl butyrate 

 used. 



4. Platinum black synthesizes butyric acid 

 and ethyl alcohol into ethyl butyrate. The odor 

 of ethyl butyrate appears in a short time and 

 increases with the increase in time. 



