The findings of these investigations will be presented in more 
or less detail in the following discussions. 
RELATION OF WASHING AND SCALDING TO THE WEIGHT OF SPINACH. 
Washing removes, of course, most of the adhering dirt and is a 
very necessary part of the preliminary treatment of vegetables for 
canning. Its effect upon the weight of spinach, and some of the 
other vegetables, was noted particularly. As is to be expected, 
there is a marked increase in weight, due in part to the taking 
up of water by the tissues, but especially to the adherence of water 
to the surface of the leaves. The increase varies with the nature 
of the material, viz, its freshness, the fineness or coarseness of the 
leaves, the amount of petiole and stem tissue present, etc. In these 
tests, the water held in this way amounted to 40 to 50 per cent of 
the original weight of the spinach. 
During scalding, this increase in weight may largely or entirely 
disappear, so that the weight after scalding is actually less than that 
of the original unwashed material. Several factors influence this. 
In these experiments, with material fresh from the field, there was a 
loss in weight during scalding amounting to 4 to 9 per cent of the 
original weight. In other samples purchased on the open market a 
gain of 7 per cent was noted. The amount of gain or loss is depend- 
ent upon the freshness of the material, the amount of soluble sub- 
stances lost into the scalding water, and the extent of draining and 
evaporation before filling into the can. 
SHRINKAGE OF SPINACH. 
When fresh spinach is plunged into boiling water or exposed to 
live steam the turgidity of the cells is promptly lost and the tissues 
collapse. A much closer pack is thus made possible. The extent of 
the shrinkage varies with the age of the spinach, the extent of trim- 
ming, the extent of the stirring, and the temperature of the bath or 
steam. To get the maximum shrinkage, the heat must penetrate to 
all parts of the mass, which means that piling up or packing together 
must be avoided. 
The extent of the shrinkage in these tests was found to vary from 
50 to 60 per cent of the original bulk. Differences between the effect 
of a 2-minute scalding period and a 4-minute treatment were too 
small to be significant; and the differences between the hot-water 
treatment and the exposure to live steam in causing shrinkage were 
believed too small to be important. All that is necessary to get com- 
plete loss of turgidity is to bring the temperature of the tissues to 
100° C. If this is accomplished in 1 minute, most of the shrinkage 
occurs during this minute. The freedom with which heat is allowed 
to penetrate into the mass seems to be the prime practical considera- 
tion. This is of particular importance in home canning, where the 
steaming must be done in small receptacles and with a limited steam 
supply. Considerable difference in the rate of shrinkage by steam 
and by water treatment would be found under these conditions, the 
slow steaming requiring a considerably longer time to effect the 
same result. 
In these experiments, there was 4 to 8 per cent more shrinkage 
when the scalding was done in a 2 per cent brine than when dis- 
