EXAMINATION OP MEATS 1 59 



form of the Gaertner group of bacilli has been the infecting organ- 

 ism. The Gaertner bacilli are large coli-typhoid types which 

 occupy a position intermediate between the chemically active 

 colon group and the chemically inert typhoid group, and includes 

 B. enteritidis, B. typhi murium, B. suipestifer and B. paratyphosus 

 B. Sausages and ham are the commonest sources of botulism. 

 From the anaerobic character of the bacillus it follows that poison- 

 ing is rarely due to the eating of fresh sausage and pork. Invasion 

 of meats by B. botulinus can take place only when the necessary 

 anaerobic conditions exist, as for example when a ham is stored at 

 the bottom of the pickling vat and entirely covered by the pickling 

 solution, and in the interior of insufi&ciently cooked sausages and in 

 stored masses of sausage meats. 



The use of the compound microscope in the examination of 

 meats and meat preparations is still in its infancy. The work done 

 shows very clearly that with more experience very valuable in- 

 formation can be obtained from the microscopical examination 

 regarding the quality of meats of all kinds. It is highly probable 

 that the microscope will show diagnostic differences in the muscu- 

 lature of different animals, thus making it possible to determine the 

 source of the meat. 



Considerable attention has already^been given to the micro- 

 scopical study of fat crystals derived from the fats of different 

 species of animals. So-called rancid fats or fats which have aged 

 considerably, even though they may not yet give evidence of ran- 

 cidity to the unaided senses, will show more or less abundant 

 crystalline structure, arranged in clusters, which may be readily 

 seen under the low power of the compound microscope. These 

 crystals are not apparent in fresh fats, but are generally more or less 

 abundantly present in canned meats and soup stocks containing 

 animal products, in meat extracts and in other meat derivatives 

 having fat admixtures. The presence of crystal clusters indicates 

 fat decomposition and these are therefore an indication of the 

 quality of the meat product containing them. The degree of ran- 



