490 



boiliiij; water bath to bring thera to this temperature. To this 1 c. c. 

 of fat, 4 c. c. of ah'oholic potash sohitiou (prepared by dissolviiij; 1(K> 

 grams potassium liydrate in as little h(>t water as ]K»ssible and then 

 diluting to 1 litt-r with alcohol), and a eouple of ]>i«M-es of i)umiee stone 

 are added and the tube hung in a water bath. In from 10 to 15 

 minutes the saiK»nitieation is eomi»h't<'<l and the ah-olud evaporated. 

 The sai)onitied fat is dissolved in about 10 e. e. of hot watrr and the 

 fatty acids separat«Ml by adding ."> e. e. sulphurie acid (1 : 4), heating in 

 a water bath, adding hot watrr suftieient to bring the dissolved fatty 

 acids up into the graduated part of the tube, and then whirling in the 

 centrifuge for 2 minutes. The voluiiu' is then read otf at 100° C. The 

 operation is said to lequire about iialf an hour. In numerous determi- 

 nations by the author the fatty acids constituted in butter 90 to 91 per 

 cent, in margarine 94 to!>.") i»er cent, and in other fats 9.") to 97 per cent of 

 the fat taken. Finally, it is jn-oposed to determine the index of refrac- 

 tion of the melted fat by means (tf a I'ulfri«h refractometi-r. 



The author claims that in a short time and without taking any weights, 

 valuable data forjudging of the cliara(t<-r ot butter are secured by the 

 method just deserit>ed. 



Concerning the direct absorption of ammoninm salts by certain 

 plants, A. B. Griffiths iClinii. Xeirts, 64 {ISUI), p. 1/7).— The following 

 experiments ai«' in eonlii niatioii of results ])re\i(»usly reached by Miintz, 

 who found that the io<»ts of certain jdants (beans, barley, hem]t, and 

 corn) were <'apable of absorbing ammonium salts without the latt«'r 

 iK'ing first converted into nitrates. 



Young bean plantlets were immersed in a solution (»f coppt-r suli)hate 

 for ;{0 minutes to destroy any nitrifying organisms that might be present, 

 then washed in st«'rili/.«'d distill«'«l wat<'r, and the roots i)hued in a 

 sterilized culture solution composed as follows: 1 liter distilled water, 

 1 gram ])otassium chloride. O.d.". gram ferrous carbonate, and ().."> gram 

 ea<"h of sodium chloii<le. cahiuni sulphate, nnignesium sulphate, trical- 

 cic i>hosi)hate, and ammonium suli)hate. Only i)ure chemicals were 

 used. The cultures with the ]>lanth'ts w«'re ]ilace«l uiuler sterilized 

 bell glasses and supi»lied with air filti-rcd through cotton wool to ster- 

 ilize it. The plants grew well for 4 weeks, although the culture medium 

 containiMl nitrogen only as ammonium sulphate whose nitrification 

 was guarded against. N()t a trace of nitric nitrogen c«ndd be detected 

 in any of tlu' twenty-four culture solutions at the end of this time. 

 The percentage of ammonium sulphate in the solution, which was 

 0.05 at the beginning, was found to be diminished to 0.027 at the end. 

 During the growth of the i>lants no luxlules w«'re formed on the roots, 

 indicating that no nitrogen was derived from the air. 



Although in nature the ammonium salts may, as a rule, be changeil 

 to nitrates before they are taken ujt by plants, these e\]»eriments seem 

 to show that under certain cir«umstances unchanged ammonium salts 

 may be directly appropriated by plants. 



