MICHIGAN ACADEMY OF SCIENCE. IVn 



Tlie dilutions used were 1 to 50, 1 to 100, 1 to 200, 1 to 500, 1 to 1000, 

 and 1 to 2000. A test quantity of about 25 cc. of a solution was placed iu 1 

 liter flask, and the series arranged in the laboratory so as to present uniform 

 conditions. The results were very consistent. Blackening began with the 

 stronger concentrations within an hour or two. The weaker solutions gave 

 much slower response, the response being in proportion to dilution. l-20()0 

 solution gave no blackening, the tissues of the apple wizening before any 

 effect was seen. 



The above experiment was carried on in duplicate, lialf of the flasks 

 being in dark and the other half in light. There was no noticeable difference 

 in the two sets. 



The influence of heat uiwn the blackening by phenol was in general to 

 speed up the response. Apples put in tlie 25" or 37.5° incubator blackened 

 more rapidly than those at room temperature, but the drying of the fruit in 

 part compensated for the more rapid discoloration. 



The volume of air in which the fumes may distribute themselves Is 

 important. A series of flasks of various sizes, 50 cc, 500, 1,000, 2,000 and 

 3,000 were prepared with 20 cc. of 1-50 phenol in each. Bits of apple were 

 fastened with pins to the tight-fitting corks of the flasks. Within an hour 

 l»lackeniug at the edge of the pieces in tlie smallest flask was plainly visible. 

 In the largest flask blackening did not take place for several days. At tliat 

 time the pieces in the smaller flasks (up to the liter) were jet black, while 

 the 1,000 cc. and the 2,000 sizes had pieces which were conspicuously dis- 

 colored. 



To determine something of the nature of the reactions an apple was 

 dropped in boiling water for 5 minutes so that a circular sector approxi- 

 mately 1 inch in diameter was killed. At the border of this spot, the tissue 

 was somewhat discolored and the disorganization of the tissue passed from 

 complete to partial to unnoticeable. The rest of the apple was normal. The 

 apple was then exposed to phenol fumes and it was found that the part of 

 the apple which was boiled gave no reaction, the "half-killed" portion gave a 

 feeble reaction, the normal remainder blackened in the usual manner. The 

 blackening seems to be a response of living cells. 



The effect of phenol on juice squeezed from sound apples was tried, by 

 adding various concentrations of phenol under various conditions to the 

 cider. The general effect of phenol was to make the liquid a darker brown. 

 This discoloration showed only at the top of the solution. It did not take 

 place with boiled apple juice. It was absent when the uncooked juice was 

 covered willi oil. The more pulp cells the juice contained, tlu; more the dis- 

 <-olorali(Mis. If I he juice was tillered (o remove pulp cells no l»Ia<keniug look 

 place. On centrifuged piUp cells the deepening of color was evident, after 

 exposing them to strong phenol solution. The experiments with cider are 

 very important and more work must be done along this avenue of attack. 



