82 MASS. EXPERIMENT STATION BULLETIN 378 



Fruit Juice Concentration. (Lowell R. Tucker.) Fruit juices were con- 

 centrated by freezing and centrifuging. Machinery was constructed in 

 cooperation with C. I. Gunness and a method developed for small scale 

 operation at refrigeration plants. The qualities of the fresh juices were 

 changed very little by freezing concentration and subsequent dilution. 

 The degree of concentration that could be obtained without serious loss 

 of soluble solids was often limited by the viscosity of the juices. This 

 limitation was greatest with juices from cooked fruits because of their 

 high viscosities. Highly viscous juices, such as cooked blueberry, cur- 

 rant, peach, and apple, could be concentrated to two-thirds to one-half 

 volume. Less viscous juices, as elderberry, strawberry, and uncooked 

 apple, could be concentrated to one-third to one-fifth volume. Cooked 

 blueberry juice treated with pectinol had its viscosity so thoroughly re- 

 duced that it could be efficiently concentrated to 45 percent soluble solids, 

 about one-fiftli volume. 



DEPARTMENT OF HORTICULTURE 

 R. A. Van Meter in Charge 



Propagation of Hemlock. (Harold S. Tiffany, Waltham.) Tests on 

 the propagation of Canadian hemlock (Tsuga canadensis) from cuttings 

 were undertaken ( 1) to determine the effect of various constant temper- 

 atures and certain growth substances on hemlock cuttings, and (2) to 

 secure uniform, own-root stock for fertilization experiments. 



Cuttings were made up (Series I on Dec. 5-9, 1939; Series II on Jan. 

 30-Feb. 1, 1940) in lots of twelve for each of eighteen treatments, dupli- 

 cated at temperatures of 60°, 65°, 70°, and 75° F. Temperatures were 

 constant, maintained by electric cable and thermostat, with the exception 

 of the 60° bench which fluctuated from 58° to 62° F. Treatments consisted 

 of indoleacetic acid at 15, 25, and 50 mg. per 100 cc. for 16, 24 and 40 

 hours; indolebutyric acid in the form of Hormodin A (45 and 60 BTI 

 units for 16, 24 and 40 hours); Hormodin Powder No. 3; and no treat- 

 ment. The cuttings w^ere placed in a medium of half sand and half peat 

 in open benches under cheesecloth tents and kept fairly moist. 



Except for slight indications (at 75° and 70° F. only) there were no 

 roofings in check treatments. These initial rootings died before the end 

 of sixteen weeks. 



At nine weeks, a single treatment of the December cuttings (Hormodin 

 A. 45 BTI units for 24 hours at 75° F.) showed outstandingly rapid rooting, 

 with a 75 percent showing of fairh^ massive root systems. The 16-hour lot 

 with this treatment fell to 37 percent, while the 40-hour treatment was 75 

 percent with less strong root systems. Since increased concentration of 

 this treatment and lower temperature did not raise the percentage of 

 rooting, there is a possibility that a still higher temperature with a lighter 

 concentration would bring a higher percentage of rooting. 



At sixteen weeks, 100 percent rooting resulted from thirteen treatments 

 of cuttings in Series II. The most successful rooting (100 percent large 

 root systems) resulted from indoleacetic acid 15 mg. per 100 cc. for 16 

 hours at 65° F. The percentage of rooting with this treatment fell to 90 

 at 70° F., and to 80 at 60° F., showing only a fair constancy for the treat- 

 ment. With 24-hour immersion of the cuttings, however, this treatment 



