SPOXTAXE(A'S CHANGES IX MILK 125 



bits (in order to te.st it for tubercle bacilli) Friis discov- 

 ered that 15 of the 28 samples contained bacteria wMch 

 caused either peritonitis or abscesses or pysemia. 

 Guinea pigs were generally useless for his experiments 

 because they all died of peritonitis. Similar results have 

 been obtained by many others. 



The forms of bacteria considered in this connection 

 are chiefly streptococci, staphylococci and members of 

 the colon group, some of which are generally present, 

 although, perhaps, in quite small amounts, in market 

 milk; besides these, there are still many other kinds, 

 some of them occurring regularly, in small numbers, and 

 some are only met with now and then. Where dn these 

 bacteria come from? Primarily from the dirt that gets 

 into the milk when it is drawn, — it is a well-known fact 

 that the excrement contains numerous, and sometimes 

 pathogenic, Ijacteria. They may also come from cases 

 of mastitis and metritis in the sta1)le; moreover the^e 

 forms of bacteria are widespread and ]irobably they 

 very often occur in cow stables, as is shown 1)> the fre- 

 quent occurrt'nce of calf cholera. " Calf cholera " is a 

 common name for a grouj) of fatal diseasi's of new-born 

 cahes among which the most usual forms are na\el 

 infection (most fre(iuently caused by streptococci, colon 

 bacilli and pseudo-colon bacilli) and diarrhoea or dysen- 

 tery of calves (in most cases caused by colon bacilli). 



It does not follow that all milk containing strepto- 

 cocci or the other bacteria referred to above is harmful 

 or dangerous. But if these are present in large num- 

 bers, they make the milk susi)icious and there are many 

 evidences that such milk has been most injurious. It is 

 highly probable that a very great part of the gastro- 

 enteritis, so harmful to small children, is traceable di- 

 rectly to these bacteria. The fact that the mortality 

 among small children in general has decreased to a great 



