GROWTH OF BACTERIA IN NORMAL MILK. 29 



utterl}' ruin the experiment. Fortnnatel}^ they are not very 

 abundant, and while they have frequently rendered the exami- 

 nation impossible, they have not seriously- interfered with the 

 value of the experiments. There are, as stated, possibl)^ three 

 species which differ somewhat in the rapidity of their growth. 



The column headed slozv liquefiers consists of a large number 

 of species which we have as yet made no attempt to differentiate 

 in these experiments. They can be quite readily differentiated 

 on the gelatin plates because the colonies are ver}- different 

 from each other, but in our previous work we have not made 

 any attempt to do it. 



The bacteria tabulated in the other columns in the tables are 

 species which are present in smaller numbers and with greater 

 irregularity. These organisms maj^ perhaps be regarded as 

 normal to milk, but they are by no means constant and each 

 sample of milk differs from the other chief!}' in the variety and 

 the number of these miscellaneous types of bacteria. Some of 

 them are more connnonly found than others, but none of them 

 appear with much constancj- and, as wdll be seen by the ex- 

 amination of the following tables, rareh^ do the}' develop in the 

 milk in such a way as to suggest that they are of any consider- 

 able importance. Some of them appear to be quite incapable 

 of adapting themselves to the conditions and fail to grow; others 

 multiply slowl}^ but even to the end of the experiments are 

 only present in small numbers; they are, therefore, of far less 

 significance in the milk than the bacteria in the first eight 

 columns. 



No attempt will be made at this place to describe the species 

 which are thus tabulated. Some of them have already been 

 described in the "Classification of Dairy Bacteria," given in a 

 previous publication of the Station;-'^ others are being now, or 

 have been, worked out in our laborator}', and will be described 

 in a revised edition of this classification which will be pub-' 

 lished at some future time. For the purpose of the experi- 

 ments here given it is quite unnecessary to describe the 

 character of the different species; thej^ may be referred to 

 simply by number or by letter, with the understanding that in 

 other publications the characters of the species are or will be 

 given in detail. 



* Storrs Expt. Sta. Rept., 1S99, pp. 13-68. 



