532 H. J. CONN 



Lugol's iodine solution should be used (1 iodine: 2 KI : 300 water.) 

 The counter-stain may be selected according to personal preference. 



Basic f uchsin (1 : 10) 



Safranin (1:10) 



Eosin (saturated alcohol) 



Bismark brown (2 per cent) may be used, but the staining period 

 should be longer. 



In making reports be sure to specify the counter-stain used. 



Of these two formulae the one containing anilin (A) was 

 selected because in a series of preliminary tests made with 4 

 different samples of gentian violet and using 20 different 

 technics, this particular formula was among the best if not the 

 very best. The ammonium oxalate formula (B), however, 

 proved almost if not quite as good in these preUminary tests 

 and the solution keeps indefinitely. It was such a new formula, 

 however, that it did not seem best to include it in the present 

 series of tests as a regular formula; hence formula (A) was se- 

 lected for this purpose with the ammonium oxalate method as 

 an optional formula, in order to get some information as to how 

 well the latter compared with the anUin formula. Five investi- 

 gators, it will be seen, used formula B and obtained as good 

 results with it as with formula A. 



The results of the tests are given in table 1. In this table 

 the same method of indicating results is used as w^as employed 

 in the earlier article. The significance of the symbols used is 

 as follows; 



E, excellent 

 G, good 



F, fair 



U, unsatisfactory 



One column of this table indicates the average rank of the first 

 tests, that is those reported in the previous paper, and another 

 column indicates the average rank in the present series of tests. 

 The first thing to be noticed in the present series of tests is 

 that all the samples have nearly the same rank in their average 

 grade, which is generally G, G 4- or G - . Provided all the results 



