No abstract

VOl. 47 the enzyme content. It is impossible to determine without actual experimentation which drying temperature should be employed.The data show that it is impossible to dry certain tissues without changing their sugar content. In order to analyze such tissues, the alcohol method of preservation recommended by Davis, Daish and Sawyer must be adopted.22 This method was tried by the writers with beet leaves and corn ears and was found to be effective. It is interesting to note that Appleman and Arthur16 used the alcohol method in preserving their corn samples for analysis. Summary 1. . 3.Drying a t temperatures below 65' changed the sugar content of beet, corn and barberry leaves and corn ears.Drying a t 65" and 80' proved successful with beet and corn leaves, which are tissues that dry rapidly.Killing and drying for 24 hours a t 98' lowered the sugar content by caramelization and leaching in beet and corn leaves and corn ears and caused hydrolysis of the sucrose in barberry leaves.The Spoehr method of heating the tissue in a closed vessel for 30 minutes a t 98' raises the temperature to the killing point more quickly than direct heating a t the same temperature in an open system. It is suggested that subsequent drying should be a t a reduced temperature in a wellventilated oven, thereby minimizing losses by leaching and caramelization.It has been shown that the method of preservation by heat is inapplicable with certain tissues. In such cases the method of preservation with alcohol is the only alternative. 4. 5.The first paper of this series1 outlined a method of comparing the reactivities of the halogen atoms in organic compounds by measuring the rates a t which the organic halides reacted with potassium iodide in acetone. This general reaction (RX + K I + R I + KX) is free from side reactions such as hydrolysis and formation of unsaturated or cyclic compounds and, therefore, significant measurements can be obtained with 22 Davis, Daish and Sawyer, J . Agr. Sci., 7, 255 (1916). TRIS JOWRNAL, 46, 232 (1924),

No abstract

Ever since the days of the Garden of Eden mankind has been interested more or less in fabrics of either animal or vegetable origin. We are still copying, in a way, the procedure of that day, only using mulberry leaves, and at present are fashioning our fabrics from the stalk fibers and even from the wood itself. The most important textile fibers at the present time are linen, wool, cotton, silk, and rayon. Some of the very oldest fabrics which are in existence come from the tombs of Egypt. These were undoubtedly the clothing of those early JOURNAL OF CHEMICAL EDUCATION

No abstract