PROGRESS OF THE STATIONS. * 25 



Foi aofP'^ ivnnot has boon used in tho ])rodiu'ti()n of curd, and it has 

 boon supposod that nothini"- else could take its place. An extended 

 study of the action of rennet by the New York State Experiment Station 

 led to the conclusion that its effects" in curd production are due to a sin- 

 gle ferment whose action is essentially like that of pepsin. This raised 

 the question whether ordinary commercial pepsin could not be used in 

 the place of rennet. The Wisconsin Station and the Ohio State Univer- 

 sity have demonstrated that pepsin may be so used with entire success, 

 and tests with i)opsin on a conunorcial scale in an Ohio choose factory 

 have resulted in the production of choose of hi>ih (juality. Some of the 

 advantages of scale pepsin over rennet extracts are that it is of more 

 uniform strength, keeps better, especially in warm weather, and is 

 free from bacteria and molds. 



According to the traditions of cheese making, a temperature of at 

 least 70^ F. has been considered the proper one for ripening cheese, 

 ])ut investigations have shown that while high temperatures hasten 

 changes in the casein, since ferments and bacteria are then more active, 

 heat also increases the activity of injurious germs and prevents proper 

 control of the ripening. Ilonce, too warm curing rooms are one of the 

 greatest causes of poor cheese. 



Taking up this line of work, the Wisconsin and New York State 

 stations have made extensive experiments in curing cheese at low tem- 

 peratures, and recently the United States Department of Agriculture 

 has cooperated in this work. Cold curing at from 40^ to 60° F. has in 

 this way been shown to be entirely practicable, and to result not only 

 in improved quality, but in a saving from shrinkage which will more 

 than cover the exponso of artificial cooling. Cheese makers are now 

 cojivinced that thov have been holding their cheese at too hio-h a tem- 

 porature, and there is a very general movement among them to 

 provide facilities for lowering the temperature and keeping it down 

 even in the hottest weather. 



Another good illustration of the practical value of the accumulated 

 results of experiment station work ma}' be found in the sumn)ary of 

 the investigations on apple growing contained in another part of this 

 report. From this it appears that the stations have issued more than 

 17<> ))ullotins on this subject. Much useful information regarding the 

 host gonoi-al conditions for apple growing, and the varieties ada})tod 

 to diffoi'ont localities, has thus t)oon disseminated, l)ut besides this the 

 results of a large )uunl)er of original investigations have l>een repoi'ted. 



Studios of the flowers of apple trees have shown that some varieties 

 of apples are self-sterile, while others are good pollenizers. In this 

 wa}' the unpioductiveness of many orchards is explained, and the way 

 to remedy this is pointed out. The conditions under which the pollen 

 germinat(\s, and how this process is afl'ected by heat, rain, and cold, as 

 well as the value of ))eos as agents in the distribution of pollen, have 



