BACTERIOLOGY OF SARDiyES 185 



SESSIONAL PAPER No. 38a 



For the sake of convenience I have divided the strains of bacteria isolated at St. 

 Andrews and at various times during the fall and winter into two main classes: — 

 Class I. — Gas-producers. 

 Class II. — Non-gas-producers. 



For obvious reasons my attention has been principally confined to the gas pro- 

 ducers. Class I, and it is to the descriptions of these that the cultural part of the report 

 is chiefly directed. 



Regarding the influence of those organisms included in Class II on the condition 

 of the fish in swelled cans, I am not in a position to express any opinion. Many of 

 them have, however, been submitted to certain preliminary tests, the results of which 

 are recorded, pages 211-213. Beyond this I have not gone, and no comments respecting 

 the class are made. 



Concerning the gas-producers, Class I, 8 strains have been described morpho- 

 logically, biologically and biochemically. The detailed descriptions are found on pages 

 192-207. On pages 208 and 209 a summary arranged in tabular form is shown. 



The number of cultures described in Class I, and those more briefly referred to in 

 Class II, bear no relationship to the total number of cultures isolated in the course of 

 the work. As was to be expected, preliminary tests of a differential nature revealed 

 the fact that many strains were in duplicate, and sometimes even in triplicate. By 

 repeated series of tests the duplicates or triplicates were gradually eliminated. In the 

 pages devoted to the cultures in Class II, pages 211-213, a note is added as to the 

 comparative frequency of the respective strains. In eliminating strains from the 

 cultures in Class I, greater precautions were taken on account of their closer relation- 

 ship to the abnormal condition of the cans. Some of the final cultiires described 

 represent the individual strains, after the elimination of as many as four or five 

 strains which had been found to have the main characteristics in common. Three 

 cidtures of Class I were finally eliminated to avoid duplication in description, just 

 prior to the preparation of the manuscripts, these being identical with cultures, 34, 

 37, and 64, respectively. 



To continue the statement as to the project of the investigation, initiated on page 

 184, it is further required, that in order to confirm the work up to the present and 

 complete the investigation it is desirable: — 



9. That many more cans shall be examined and the contents cultured. 



10. That if possible the source of the responsible organisms be determined, 

 and also the stage at which infection takes place. 



11. That experiments be conducted both under laboratory conditions, and 

 under conditions prevailing in the canning factories, with a view to deter- 

 mining the most satisfactory means of eliminating " swelling." 



12. That possibly the pathogenicity or degree of pathogenicity of the strains 

 proved responsible for the " swelling " be determined by inoculation into suit- 

 able laboratory animals. 



Arrangements have been made by Dr. Huntsman whereby during a later season I 

 shall have opportunities of determining if possible the source or sources of the causal 

 organisms of the swelled condition of cans of sardines. 



The future scope of the laboratory work will necessarily include examination of 

 swelled cans of other varieties of fish, including those of which mention is made on 

 page 183. 



When visiting the canning factories last summer the manager of one of the 

 largest of these told me that a pressing problem with which he had to contend was 

 the frequent appearance among sardine cans of what are termed " sour flats." The 

 condition is one of which there appears at present to be no satisfactory explanation. 

 The product is rendered unmarketable, and the condition is one which cannot be 

 detected until the cans are opened. 



38a— 13 



