BY R. GBBIG-SMITH. 155 



malie. 70.9 ; and citric, 153. The time in minutes recjuired for a 99 % extrac- 

 tion in a Partliiel-Rose apparatus holding 30 c.c. is obtained by dividing the Dis- 

 tribution Equivalent by 0.04. 



From this one gathers that lactic acid is extracted in il hours in a Parthiel- 

 Rose apparatus holding 30 c.c, while in a Schoorl apparatus it took 8 hours 

 dealing with 20 c.c. The kind of apparatus is therefore of some moment. The 

 Schoorl apparatus can easily be obtained and is the one I have used. A test 

 with it upon 100 c.c. of liquid containing 0.25 grams of succinic acid showed 

 that 79 % was extracted in 7 hours and 99 % in 12 hours. The presence of 

 5 % of dextrose made no difference in the speed of extraction. 



The fixed acids from the film yeast were contained in a fairly strong solu- 

 tion of sugar with ammonium and other salts and measured about 100 c.c. After 

 certain periods of extraction the bulk of the ether was distilled off, the remainder 

 air-evaporated and the residue titrated with tenth-normal soda. 



+, . , J, , , . Acid extracted a-s c.c. 



Period or extraction n i. i., , 



or tenth normal. 



7 hours 48.4 or 53 % 



19 hours 23.3 71.7 78 % 



31 hours 9.3 81.0 86 % 



43 hours 5.5 86.5 94 % 



55 hours 5.3 91.8 100 % 



In another test the acids had l>e€n extracted and the calcium salts, insoluble 

 in 70 % alcohol, were treated with sulphuric acid and percolated with ether. The 

 volume measured 50 c.c. 



„ . J J, , ,• Acid extracted as c.c. 



Period or extraction r> , ,, , 



of tenth normal. 



7 hours 81.83 or 61 % 



19 hours 29.95 111.78 83 % 



31 hours 15.05 126.83 95 % 



43 hours 6.93 133.7(1 100 % 



Curves prepared from these figures showed that they were of the nature of 

 monomolecular reactions, while an extended examination of the portions showed 

 that succinic acid was the only acid present. The examination was extended 

 because succinic acid is not so definite in its behaviour as one is led to suppose. 

 The slight solubility of the calcium and of the silver salts causes it to appear in 

 places where other acids are expected. For example, while a pure salt of 

 succinic acid was completely precipitated by silver nitrate and contained the 

 theoretical amount of silver, the neutral salt of the acid obtained from the yeast 

 culture was not completely precipitated, for the quantity was lower than was 

 expected from the neutralisation numbers and the filtrate contained a con- 

 siderable amount of the acid. So much so that it almost appeared as if there 

 were more than one kind of succinic acid. The melting point was normal whiltp 

 the silver content of the silver salt was low, 62.4 and 62.6, as against the 

 theoretical 65.07 %. There was always a small ciuantity of a syrupy substance 

 associated with the acid. It was too small in amount to determine its nature, 

 but it influenced the crystallisation of the pure acid. It is possible that it may 

 have had something to do with the solubility of the silver salt. 



An attempt was made to determine the nature of this syi'upy acid. The 

 mother-liquor, after the 55 hours' extraction (see above) was treated with an 



