52 



Scientific Proceedings (103). 



The tumor may occur in any segment of the larva but seems 

 to occur more often in the twelfth and thirteenth segments. 

 When the tumor occurs in the thoracic region, there may be an 

 ingrowth of tumor cells into the imaginal discs of the appendages 

 checking the development of these parts. 



The cells of the tumor are rounded or polygonal in shape and 

 show the presence of pigment. 



31 (i49i) 



The suitability of the "Bachman Test'* for water-soluble B. 

 By Walter H. Eddy and Helen C. Stevenson. 



[From Teachers College, Columbia University, New York City.] 



Two recent publications by Drs. Bachman 1 and Williams 2 

 dealing with the vitamine requirements of yeasts suggest that the 

 methods developed are adaptable to quantitative measurement of 

 vitamine content (B variety). At the suggestion of the senior 

 author Miss Stevenson has conducted experiments with both 

 methods and in this report are presented some of the results with 

 the Bachman test. 



Briefly this method consists in planting yeast cells in a culture 

 medium (Nageli's solution: 100 c.c. distilled water; 10 gms. 

 dextrose; 1 gm. ammonium nitrate; 0.05 gms. calcium phosphate; 

 0.5 gms. potassium acid phosphate; 0.25 gms. magnesium sulfate) 

 contained in a Durham or Smith fermentation tube and incubating 

 the tubes at 28-32 0 C. to obtain gas formation. To these tubes 

 are added vitamine "B" extracts from various sources and Dr. 

 Bachman's results showed that in the absence of such extracts gas 

 formation either fails to take place or at least very slowly. 



Our experiments aimed to confirm Dr. Bachman's results, to 

 determine whether the method gave promise of use quantitatively 

 and whether it might be used to detect the "B" vitamine quali- 

 tatively. The results of our experiments follow: 



1 'The " Vitamine Requirements of Certain Yeasts," by Freda Bachman, Journ. 

 Biol. Chem., XXXIX, 235 (1919). 



1 "A Simple Biological Test For Vitamines," by R. W. Williams, Journ. Biol. 

 Chem., XXXVIII, 465 (1919). 



