Carbon dioxide content of milk

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C a r b o n Dioxide C o n t e n t of Milk.mLuclL'S L. VAN SLYKE and RICHARD F. KE~LER of the New Y o r k A g r i c u l t u r a l E x p e r i m e n t Station at G e n e v a h a v e m a d e a research on " T h e Carbon Dioxide C o n t e n t ' a s a Basis for D i s t i n g u i s h i n g H e a t e d f r o m U n h e a t e d M i l k " (Journal of Biological Chemistry, 192o, xlii, 41-45). N o r m a l milk in the u d d e r has an a v e r a g e carbon dioxide content of app r o x i m a t e l y IO per cent. by volume. Immediately after the milk is d r a w n f r o m the udder, either b y hand or by a m i l k i n g machine, its carbon dioxide c o n t e n t usualy lies b e t w e e n 4 and 4.5 per cent. by volume. W h e n fresh milk w a s allowed to stand, its carbon dioxide c o n t e n t d e c r e a s e d and attained a m i n i m u m value of 3 per cent. by v o l u m e f r o m t w e n t y to f o r t y hours after milking. Agitation, such as milk m a y u n d e r g o on the f a r m and d u r i n g m a r k e t i n g , had little or no effect in reducing the per cent. of carbon dioxide in the milk. A f t e r p a s t e u r i z a t i o n b y the flash s y s t e m or b y heating for t h i r t y m i n u t e s at either 62 ° or 78o C., milk seldom contained more than 2.5 per cent. carbon dioxide b y volume, and usually c o n t a i n e d less. " T h e r e f o r e , it a p p e a r s safe, in general, to a s s u m e t h a t milk c o n t a i n i n g less t h a n 2.5 or 3 per cent. of carbon dioxide by volume has been heated to the temperature of pasteurization." J. S . H . T e s t s of A u x i l i a r y Condensers. C. WALDIE CAIRNS and J. MORROW. (North-East Coast Institution of Engineers and Shipbuilders, May I7, 1 9 2 o . ) - - T h e p a p e r is based on a r e p o r t to the Council b y the authors, on tests carried out by t h e m for the purpose of d e t e r m i n i n g the relative p e r f o r m a n c e s of certain auxiliary c o n d e n s e r s for use on b o a r d ship. F o u r condensers were tested, viz., two of "Contraflo" type, one of cylindrical, and one pear-shaped. T h e p a r t i c u l a r c o n d e n s e r s are described in detail. T h e exp e r i m e n t s c o n d u c t e d are described and c o m p a r a t i v e tables of t h e results f r o m the tests m a d e upon each c o n d e n s e r are given. A s t a t e m e n t of conclusions f r o m t h e s e results c o m p l e t e s the report. T h e E x i s t e n c e of H o m o g e n e o u s G r o u p s of L a r g e Ions. O. BLACKWOOD. (Proc. Nat. Acad. Sciences, May, I 9 2 o . ) - - W h e n distilled w a t e r is s p r a y e d large ions are produced, w h o s e exact n a t u r e is as y e t u n k n o w n . I t is m a i n t a i n e d by some t h a t these ions are of only a few definite sizes. T h i s w a s i n v e s t i g a t e d b y s t u d y i n g the flow of an air s t r e a m c a r r y i n g such ions t h r o u g h the space b e t w e e n t w o concentric cylinders, b e t w e e n which there w a s a difference of electrical po284