618 



SCIENCE 



[N. S. Vol. XLIX. No. 1278 



A ftitiu'e communication will show how 

 these colloid chemical facts may be used in 

 the erection of secretory models which, like 

 the salivary gland or kidney, yield " secre- 

 tions " either more alkaline or more acid than 

 the allegedly neutral (or even acid or alkaline) 

 tissues. 



It has proved impossible to find an editor 

 with space available for the details of the ex- 

 periments outlined above and previously re- 

 ported upon. They must in consequence be 

 brought out in a book. But since the making 

 of such takes time, it has seemed of interest 

 to make a preliminary report upon work which 

 has at various times been lectured upon to 

 different scientific audiences. 



Martin H. Fischer 

 EiCHBERG Laboratory op Physiology, 

 UNrvERsiTY OP Cincinnati, 

 May 5, 1919 



THE BUFFALO MEETING OF THE 

 AMERICAN CHEMICAL SO- 

 CIETY. Ill 



Testing the mildew resistance of fabrics: F. P. 

 Veitch and S. S. Levtne. A metliod has been de- 

 vised for testing the mildew resistance of fabrics 

 treated by so-called mildew-proofing processes. The 

 method takes into consideration the important de- 

 termining mold growth and is conducted in the 

 laboratory under conditions which ale highly fav- 

 orable to the development of mildew and which 

 are carefully controlled. It is briefly described as 

 follows: Six discs about 3.5 inches in diameter are 

 cut from the sample to be tested and soaked in 

 running tap water for two or three days in order 

 to wash out easily removable fungicides and fer- 

 mentable matter. The damp discs are plaoed in 

 petri plates containing ten to fifteen cubic centi- 

 meters of agar jelly from nutrient matter. The 

 plates are then incubated for seven to ten days 

 in a dark chamber at from 20° C. to 25° C. The 

 condition of the fabric as to the color, extent and 

 character of the growth are observed and recorded. 

 Following this pre-inoculation period the discs are 

 inoculated with pure cultures of several species of 

 molds and reincubated for three weeks to a month 

 and examined each week for mold growth. The 

 observed conditions are rated on a scale of t«n. 

 At the conclusion of the tests the discs are washed 

 and preserved as records. The test is a severe one 



which is borne perfectly for the full period only 

 by canvas treated by the cupra-ammonium process. 

 Its utility has been demonstrated, however, by the 

 fact that canvas which gives a rating of 6 or bet- 

 ter has not mildewed on exposure to the weather 

 at Washington, D. C, during the summer and fall 

 months. 



Testing materials for increasing tJie water re- 

 sistance of sole leather: H. P. Holman and F. P. 

 Veitch. To determine waterproofing value, several 

 pieces of sole leather which are always of the 

 same tannage and from the same section of the 

 hide but which differ in texture are impregnated 

 by immersing in the treating material for ten min- 

 utes at 60° C, followed by warming in an oven at 

 60° for fifteen minutes. Water absorption is de- 

 termined by soaking in water for twenty-four 

 hours, with periodical flexing, and weighing the 

 wet leather after removing all excess from the 

 surface. The leather is also weighed before treat- 

 ing, after treating, and in the air dry condition 

 after testing. From these weights the quantity of 

 treating material taken up by the leather, the ac- 

 tual water absorption, and the loss in weight on 

 testing are calculated in percentages. The actual 

 water absorption is calculated on the basis of the 

 final dry weight. All dry weights should be made 

 after exposing the leather to the same atmospheric 

 humidity. Eighty samples, including practically 

 all the commercial materials used in waterproofing 

 sole leather, were tested by this method. Only 

 twenty were found to waterproof sole leather 

 sufficiently to prevent its absorbing an average of 

 more than 35 per cent, of water under the condi- 

 tions of the test. This percentage was arbitrarily 

 adopted as a limit for Batisfactory materials for 

 increasing the water resistance of sole leathers. 



Method for determining the water resistance of 

 fabrics: F. P. Veitch and T. D. Jarhell. In de- 

 veloping more effective methods of making can- 

 vas water- and mildew-resistant, and for testing 

 for the War Department deliveries of canvas and 

 clothing for water resistance, it was necessary to 

 employ methods of testing that are both expedi- 

 tious and indicative of the effectiveness and dura- 

 bility of the treatment. Modifications of the old 

 bag or funnel and of the spray test have been de- 

 vised which have proved very satisfactory in that 

 all canvas given high ratings by these methods 

 have been found to be water resistant during sis 

 months of outdoor exposure throughout the sum- 

 mer and fall. Of the two, the spray test yields 

 possibly the most information. Neither the de- 



