' May 17, 1901.) 
Cape Town for eighteen months; on ac- 
count of the military situation, its effective 
eradication was neglected, and now the dis- 
It is 
this risk which San Francisco has been 
ease has roused into active form. 
running, and this risk no community has 
the right to assume. 
THE DESTRUCTION OF SEA LIONS IN 
CALIFORNIA. 
PROFESSOR WOODWARD’s wholesome address 
on the necessity of verifying theories by the 
observation of facts finds an excellent illustra- 
tion in the sea lion question in California. 
These animals, which have long been prized by 
lovers of nature as one of the great attractions 
of the coast, have fallen into disrepute among 
the fishermen because their presence was sup- 
posed to account for the deterioration of certain 
fishing grounds. So confident was the belief 
in their fish-devouring habits that their des- 
' truction—or at least a great reduction of their 
numbers—was advocated and in part accom- 
plished by the State Commission of Fisheries. 
But it now appears that this belief was without 
substantial foundation. The appeal to fact has 
been made by the critical examination of the 
stomachs of slaughtered sea lions, and it has 
been found by Professor Dyche that the twenty- 
five animals examined had eaten only squids 
and other cephalopods, eschewing fish alto- 
gether. The case is suggestive of the old phil- 
Why is it that a live fish 
adds nothing to the weight of a bucket of water? 
osophieal puzzle : 
and would be amusing but for the sad fact that 
the unfounded theory has already led to the 
killing of many of these graceful creatures. 
The investigation of food-habits by means of 
stomach examination is of far-reaching impor- 
tance. Dr. Merriam, whose letter on sea lions 
we print on another page, is engaged, through 
the Biological Survey, in the most elaborate 
SCIENCE. 
765 
study of animal foods ever made. For many 
years the stomachs of wild birds and mammals 
have been systematically collected and labor- 
iously studied, to the end that the favorite and 
the occasional foods of each species in each sea- 
son of the year, and in each part of the country, 
may become known. As each group is worked 
up the facts are published by the Department 
of Agriculture, and farmers and legislators are 
thus informed what species may properly be 
regarded as friendly, and what as hostile, to 
the interests of the people. In many instances 
it has been found that popular impressions, 
almost necessarily founded on a comparatively 
small number of facts, are altogether erroneous, 
so that war has been waged on our friends and 
protection given our. enemies. % 
ON THE VITAL ACTIVITY OF THE ENZYMES.* 
In spite of the vast amount of work that 
has been done on the soluble ferments, 
since the discovery of diastase by Kirchoff, 
in 1814, the exact chemical nature of these 
substances is, perhaps, even more of an 
enigma to-day than the nature of albumen 
itself. Indeed, beyond the fact that the 
enzymes, or at least the greater number of 
them, are albuminous, that they probably 
belong to the group of nucleo-proteids and 
that they contain phosphorus, and probably 
iron, in addition to carbon, hydrogen, 
oxygen and nitrogen, we know but little 
more concerning their exact chemical com- 
position than was known to Payen and 
* In slightly different form this paper was read be- 
fore the Cincinnati Section of the American Chemical 
Society, December 15, 1900. 
Many of the biological memoirs referred to in the 
following were inaccessible to the writer in the orig- 
inal. He, therefore, desires to acknowledge his in- 
debtedness to the following authorities: ‘The Solu- 
ble Ferments and Fermentation,’ Green ; ‘ Die Fer- 
mente und Ihre Wirkungen,’ Oppenheimer ; ‘ The 
Cel] in Development and Inheritance,’ Wilson ; 
? 
‘Plant Physiology,’ Sachs; ‘Plant Physiology,’ 
Pfeffer; Hueppe’s ‘Principles of Bacteriology,’ Jordan. 
\ 
