90 MILK AND ITS HYGIENIC RELATIONS 



boiled. The solution alone does not reduce F.M.B. in water 

 solution. 



Wedemann showed that the milk of goats (which has been 

 found by numerous observers to contain no ferment capable of 

 reducing the F.M.B. solution) will give reduction on the addition 

 of alkali in sufficient quantities to be alkaline to lackmus or on 

 the addition of ferrous sulphate. He confirmed the presence of 

 this ferment in cows' milk. 



Rullmann (3, 4) showed that formic acid could replace formalde- 

 hyde in the reduction of the F.M.B. reaction. He first showed that 

 the addition of lactose to soda had an appreciable effect in reducing 

 the time required for reduction both of M.B. and of F.M.B. in 

 boiled or sterilised milk. He also showed that lactose alone does 

 not produce this effect. 



Rullmann also carried out a number of investigations relating 

 to the restoration of the reaction in boiled milk or sterilised milk. 

 He concludes that there is a substance present in milk which is 

 capable of bringing about the reduction of Schardinger's reagent 

 at 45-5o C. apart from bacteria, and that this substance is 

 probably a ferment ; that reduction of the same reagent can also 

 be brought about at higher temperatures by substances present 

 in milk, i.e. lactose and salts, which probably assist in the reduc- 

 tion of the reagent at the lower temperature. The presence of a 

 ferment which reduces Schardinger's reagent, in milk obtained free 

 from bacteria, first shown by Rullmann, was confirmed by Harden 

 and Lane-Claypon. 



Burri and Kursteiner carried out prolonged observations upon 

 the Schardinger reaction, and they confirmed the belief of previous 

 authors that the reaction is due to the presence of a ferment whose 

 action can be simulated by the addition of alkali or ferrous 

 sulphate. They suggest the name ' formaldehydase ' for the 

 ferment concerned. They believe that the length of time required 

 for reduction depends upon the presence or absence of oxygen, 

 being prolonged when oxygen is present and curtailed when oxygen 

 is removed. Burri and Schmid had also shown in 1911 that 

 milk of a lower bacterial content, 10,000 to 30,000 per c.c., shows 

 a reduction in the time required for the Schardinger reaction if 

 it is cooled to 12 C. or boiled before testing. The authors 

 connected this alteration in reduction time with changes occur- 

 ring in the fat globules on cooling, described by Burri and 

 Nussbaumer. 



Lagane (i) found this ferment present in cows' milk unless the 

 cow is in poor health or unless she had not been milked recently. 

 The blue colour reappeared after reduction in from two to four 

 hours, being more rapid when there is a greater exposure of the 

 surface to the air. This seems to harmonise with the findings 

 of Burri and Kursteiner. Lagane showed that the sediment 

 gave no reduction, the reaction depending upon the fat. The 



