96 HISTOKY AND CAUSE OF THE COCONUT BUD-EOT. 



filter paper without leaving the slightest trace of residue other than 

 what was apparently the CaCOg. In other tubes, on the contrary, 

 there still persisted, not a distinct curd, but a residue, gelatinous in 

 appearance — a small amount in several tubes, but a large amount in 

 others. The nature of this mass was not ascertained. It was by no 

 means similar to the cheesy curd of acid formation; yet it appeared 

 to represent a coagulation of some sort. These experiments seem to 

 justify the conclusion that the major part of coagulation is caused by 

 the acid formation, but that a small amount of coagulation may also 

 be due to an enzymatic action. 



PRODUCTION OF ALCOHOLS, ALDEHYDES, AND ACETONE. 



In testmg for alcohols, aldehydes, and acetone 500 c. c. of a medium 

 consisting of peptone and dextrose, to which 10 c. c. of calcium 

 carbonate was added, was inoculated m a liter flask and incubated 

 at 37° C. In two days the organisms had produced a large amount 

 of gas which, however, had completely disappeared in seven days. 

 Then a cubic centimeter of paraffin was thrown into the cultivation 

 and the flask was connected %vith a condenser for distillation. The 

 paraffin was for the purpose of forming a thin layer over the sur- 

 face of the fluid to prevent frothing up and running over into the 

 condenser. The distillate obtained was about 300 c. c, which was 

 then tested for alcohols, aldehydes, and acetones. It was divided 

 into four portions and tested. To one portion was added Lugol's 

 iodin (iodm, 1 gram; iodid of potassium, 3 grams; distilled water, 300 

 c. c), then a little NaOH solution to the liquid, which was stirred 

 with a glass rod. Abundant pale-yellow crystalline precipitate was 

 formed, which indicated the presence of iodoform, which was very 

 evident also from the odor. This reaction indicated that either alco- 

 hol, aldehyde, or acetone was present, and further tests were made 

 for their identification. 



To a portion of the solution enough ammonia was added to make 

 the solution strongly alkaline and then gradually a solution of iodin 

 in ammonium iodid was added. A black precipitate formed,^ but 

 no other change took place, thus indicatmg the absence of acetone. 



In order to determine the presence of alcohol, 1 cubic centimeter 

 of molybdic acid was gently warmed m 10 c. c. of strong II2SO4, and 

 then a few drops of the distillate were added and warmed in a porce- 

 lain dish for a few moments. A bright Prussian-blue color resulted, 

 indicating the presence of an alcohol. 



In order to test for the presence of an aldehyde, a solution of phenol 

 in excess of sulphuric acid was made up and to it was added a small 

 amount of the distillate. The absence of any resuUing dark-red color 



' M. Scniel says (Archives M6dlcales Beiges, ser. 4, vol. 1, 1893, pp. 9-33) that acetone Is reported as 

 occurring in Bacillus coli cultures. 

 228 



