THE PROGRESS OF SCIENCE. 



383 



nucleus of the international meeting. 

 That such a unique fusion of scholar- 

 ship will be productive in itself no 

 one can doubt; but that these scholars 

 are brought together and are doing 

 their work under the control of the 



having been issued during the past few 

 months. 



In the course of the chemical studies 

 the product formed by the action of 

 rennet on milk, about which there had 

 previously been considerable doubt, was 



Palace of Education and Social Economy. 



demand for unity in knowledge, for 

 interrelation and synthesis — this 

 thought will be the living force, the 

 most powerful factor of the congress, 

 and a tremendous influence in over- 

 coming the pedantic and unphilosophic 

 narrowness of specialists in every cor- 

 ner of the realm of science." 



THE SCIENTIFIC BASIS OF 

 CHEESE MAKING. 



The processes involved in the making 

 and curing of cheese have been the sub- 

 ject of some of the most noteworthy 

 dairy investigations which have been 

 made. While the subject had been 

 studied in a fragmentary way in this 

 country and in Europe for some time, 

 little real progress was made until 

 several of the American experiment 

 stations undertook a systematic investi- 

 gation of the nature and causes of the 

 changes involved and the chemical char- 

 acter of the products formed. This 

 has gone on steadily for eight or ten 

 years, and has resulted in the working 

 out of the scientific principles under- 

 lying this very ancient art. The lar- 

 gest amount of work has been done by 

 the experiment stations in Wisconsin, 

 New York and Canada, and the names 

 of Babcock, Russell, Van Slyke and 

 Hart are especially prominent. The 

 reports of progress have appeared in a 

 series of bulletins from these stations, 

 several particularly important ones 



identified as paracasein. This was found 

 to combine with acids to form mono- 

 and di-acid salts, quite different in 

 character and in their effect upon the 

 appearance ' of the curd. In normal 

 cheese making the mono-acid salt is 

 formed, the paracasein uniting in that 

 proportion with the lactic acid pro- 

 duced in the curd by lactic-acid bac- 

 teria. These bacteria have invariably 

 been found in the milk and green cheese 

 in predominating numbers, but their 

 true function has remained until now a 

 mystery. They are indispensable to 

 the formation of paracasein monolac- 

 tate in cheese curd, and this compound 

 is found to be the starting point of the 

 ripening or curing process. 



The first step in this appears to be 

 a peptic digestion of the monolactate, 

 the rennet ferment being the active 

 agent. Kennet, which was formerly 

 supposed to contain two enzyms, is 

 found to be in reality a peptic ferment 

 and to act in all essentials like com- 

 mercial pepsin in forming soluble nitro- 

 gen compounds. In fact, normal 

 cheese has been made by the substitu- 

 tion of commercial scale pepsin for 

 rennet extract. The chemical changes 

 produced by both rennet and pepsin are 

 confined mainly to the formation of 

 paranuclein, caseoses and peptones, only 

 small amounts of amids and no am- 

 monia being formed. The action of 

 these enzyms does not appear to ex- 



