CANNED SARDINES 103 



X. 



Canned Sardines. — The cause of "Swells" or 

 " Blown Cans." 



Wilfrid Sadler^ M.Sc. 

 The University of British Columbia, Vancouver, Canada. 



INTRODUCTION. 



For many years, the fisheries of Canada have constituted a pronounced national 

 asset. Latterly, there is every reason to believe that the importance of the industry 

 is being recognized as never before by all who are concerned with the industrial pros- 

 perity of the country. Professor Prince, Dominion Commissioner of Fisheries, has 

 vccently stated that the financial returns from the fisheries have increased from 

 $10,788,000 in 1872 to $52,312,000 in 1917. Of this very satisfactory sum, a goodly 

 proportion represents the income derived from the production of canned sardines. It 

 is more or less common knowledge that the sardine of the French is a pilchard, and 

 that the North Atlantic sardine of this American continent is the young immature 

 herring. The canners engaged in the packing of sardines have found from time to 

 time that, for various reasons, a proportion of their pack has spoiled. In a recent 

 issue of the Canadian Fisherman, it is estimated that from five to ten per cent of the 

 total sardine output of the ^faritime Provinces goes to waste through spoling. Part 

 of this wastage is due to the development of "swells"; and while the trouble is less 

 common than formerly, the appearance of swells is still a matter of very considerable 

 concern., 



The methods of packing in vogue have been gradually evolved from the original 

 procedure adopted in the early days of the industry. In spite of the recurrence of 

 swells, it is only recently that efforts have been made to discover the actual specific 

 causes of the trouble. The desirability of attempting to discover these causes occurred 

 to Dr. F. C. Harrison in the summer of 1915. The matter was brought to the atten- 

 tion of the Biological Board of Canada, and in the summer of 1916, I commenced on 

 behalf of the Board, an investigation of the problem. The object of the inquiry was 

 to secure such information from experimental evidence as would enable the canners 

 to eliminate any risk of cans developing the "swelled" or "blown" condition. 



Preliminary Enquiry. 



It was decided that the work should commence at the Biological Station, St. 

 Andrews-on-the-Sea, N.B. The station is in the heart of the sardine canning industry, 

 closely situated to the important canneries of New Brunswick , Canada, and also to 

 those in the state of Maine, U.S.A. Dr. Huntsman, Biologist to the Board, and 

 Curator of the St. Andrews Station, arranged the necessary visits to the various fac- 

 tories on the New Brunswick coast ; and through the courtesy of Dr. Loomis, National 

 Canner's Asociation of America, the privilege of successive visits to the factories in 

 the state of Maine, U.S.A., was extended. It was possible during those visits to see 

 and study the general practices followed in the respective canneries or factories, and 

 also anj' variations which appeared to have a particidar bearing on the quality cf the 



