December 15, 1922] 



SCIENCE 



693 



afferent nerves .thus have the double function 

 of (1) contributing to the excitatiom of the 

 cells in the respiratory center, and (2) of eon- 

 trolling the movements of the muscles arising 

 from tliis excitation. Wliile it is undoubtedly 

 true lUiat 'the respiratory center may act auto- 

 matieally under conditions "wihich preclude the 

 effect of afferent impulses" it is our opinion 

 that its normaj activity is not wholly auto- 

 matic but partly reflex. 



F. H. Pike 

 Helen" C. Coombs 

 Columbia University 



THE AMERICAN CHEMICAL 

 SOCIETY 



(Continued) 

 division of agricultural and food chemistry. II 



The application of certain commercial dyes to 

 the reductase test on milk: Minnie F. Dresslar 

 and H. A. Webb. The decolori^atioii of methylene 

 blue by the reductases in milk furnishes a rapid 

 approximate determination of its bacterial age. 

 In order to make the test more convenient for 

 bakers, grocers, restaurant keepers, cooking classes 

 or housewives, who might wish to test milk 

 claimed to be fresh on delivery, eighty-four dye- 

 stuffs sold under trade names for household use 

 were tested. By a series of eliminations, the most 

 satisfactory ones were determined, eight in num- 

 ber. They are: "Diamond Dyes" (wool and 

 silk), cardinal, garnet, orange, turkey red; ''Eit" 

 dyes, blue, flesh, lavender, red. The deeolorizatiou 

 times, which vary for each, 'but are reasonable, 

 and the effect on various types of milk-whole, 

 skimmer, cream, pasteurized, boiled, malted, con- 

 densed, evaporated, were determined. Sugges- 

 tions for the use of the test hj non-technical 

 people are given. 



Data on the thicJcening of condensed millc: 

 Alan Leighton and Couetland S. Mudge. 



Use of frozen eggs in mayonnaise: S. K. EoB- 

 INSON. Comparisons between the fresh and frozen 

 eggs were made on batches of mayonnaise. No 

 difference in the product was noticeable, imme- 

 diately after preparation. Both products were 

 well emulsified and had good body. The following 

 physical tests were then applied : microscopical 

 examination, freezing test, incubation, shaking 

 test and effect of air and light. Not anj- of these 



6 Stewart, G. N., and Pike, F. H., Am. Journ. 

 :., 1907, six, 328. 



tests put the frozen egg product at a disadvan- 

 tage. Mayonnaise made from frozen eggs held 

 well in a warm room for thirty days. 



Changes in liens' eggs stored in water glass 

 and in lime solutions: F. C. Cook and J. B. 

 Wilson. Strictly fresh and commercial eggs, 

 which were preserved in water glass (1-10, 1-13 

 and 1-20) and saturated lime solutions. Separate 

 jars of each were stored in the laboratory and in 

 a cellar. At the beginning of the experiment and 

 after various periods samples of the eggs were 

 examined physically, bacteriologically and chem- 

 icallj'. Best results were obtained by holding 

 strictly fresh eggs in a 1-10 water glass solution 

 at cellar temperature. Changes of considerable 

 magnitude were found in water, ash and nitrogen 

 contents of both whites and yolks. Bacteria were 

 not found to be a factor in deterioration. Am- 

 monia nitrogen and acidity of fat proved to be 

 the best indices of decomposition. 



Manganese, aluminium and iron ratio as related 

 to soil toxicity: E. H. Carr and P. H. Brewer. 

 Much emphasis has been given in the past to the 

 isolation of organic toxins which were thought to 

 be the cause of soil toxicity, while in more recent 

 times the trend of investigation' has been turned 

 more specifically to soil acidity as the reason for 

 poor crop yield. Investigations which have been 

 conducted on a large variety of soils using the 

 potassium thiocj'anate method for soil acidity 

 and toxicity, described by one of the writers, indi- 

 cates that the cause of infertility of many soils, 

 supplied with sufficient plant food, is due to the 

 presence of soluble manganese compounds in some 

 cases, to aluminum compounds in other instances 

 and sometimes to a combination of the two. The 

 toxicity of soluble iron is not so apparent, as it 

 is usually associated with a considerable quantity 

 of soluble aluminum in an acid soil. The potas- 

 sium thiocyanate method has been found helpful 

 in this study, because of the color changes taking 

 place when these elements are present in the soil 

 in easily soluble form. If the soil is more acid 

 than p 5.5 a red color of ferric thiocyanate is 

 produced in the presence of soluble ferric iron 

 and if this soil solution containing manganese is 

 made slightly more basic, a green color will de- 

 velop in the liquor. The depth of the color will 

 be proportional to the amount of manganese in 

 the soil solution. This color begins to form when 

 the soil contains about 0.008 per cent, of soluble 

 manganese. The green color will be found asso- 

 ciated with nonproductive acid soils, and since it 

 is shown that manganese does not precipitate 

 as a hydroxide until a Pjj of about 7.9 is reached, 



