Both of these juices withstand heat remarkably well. Orange juice can be boiled for 10 minutes without noting any diminution of its antiscorbutic value, and lemon juice heated to 110° C. without appreciably losing its efficacy. However, orange juice undergoes some change as the result of being heated in an autoclave for 45 minutes at a temperature of 110° under 10 to 15 pounds pressure. Although 6 c.c. of this heated preparation were able to prevent the development of scurvy, the guinea-pigs did not gain nearly as well as those which received 3 c.c. of the unheated juice. It seemed as if there was a destruction of some factor apart from the antiscorbutic principle. In spite of the fact that these juices withstand heat well, they are sensitive to some other conditions. Orange juice which had been stored in the cold for three months was unable to protect guinea-pigs in the dosage of 3 c.c. per animal, resembling in its action the autoclaved juice. When this orange juice was six months old, double this quantity failed to protect; throughout this period it was kept in the ice-box and covered with a layer of oleum petrolatum to avoid the access of air or possible contamination. Harden and Zilva met with a similar experience, and state that "after storing treated (concentrated) lemon juice for about a fortnight in a cold room, a marked loss can be observed in its potency." These authors reported also that when orange juice is _rendered slightly alkaline_ it loses its antiscorbutic potency. This question was investigated in relation to canned tomato juice, as well as to orange juice, and it was found that shortly after having been rendered 0.05 N alkaline to phenolphthalein, neither of these foods had lost an appreciable amount of its antiscorbutic factor. Five cubic centimetres per capita daily of freshly-alkalized orange juice were able to cure a group of pigs which had developed scurvy on another diet. If, however, 24 hours were allowed to elapse instead of only one-half to one hour, between the alkalization and the feeding, then a considerable amount of the antiscorbutic factor was lost. The same general rule seems to hold for alkalization as for heating, _i.e._, the length of time the antiscorbutic food is subjected to the deleterious influence is fully as important as the intensity of the process. Advantage has been taken of the fact that freshly-alkalized orange juice retains its potency, in using it intravenously in the treatment of infantile scurvy.