458 MOHR, 6. WINGE’S PAPER “THE INTERACTION BETWEEN TWO 
describing as an ordinar recessive (spread) a mutant which im 
realty is a clear cut dominant. 
b. They have entirely overlooked the fact that one of their stock 
cultures, supposedly homozygous for a recessive mutant, in 
realty contained in heterozygous condition the dominant just 
mentioned and in addition another lethal gene closely linked 
to this dominant. 
This certainly must give the reader a very unfavourable impres- 
sion of their methods and statements. So elementary mistakes would 
indeed be inexcusable, and as the one who provided Dr. WINGE 
with his cultures I therefore feel obliged to give the following 
necessary rectifications. 
In 1921, when giving a lecture at a congress in Copenhagen I 
had brought with me three or four of the most common Drosophila 
mutants in order to demonstrate some striking mutant types. After my 
lecture Dr. WINGE asked me to let him have the cultures. This was. 
of course willingly granted. Dr. WINGE asked for no special infor- 
mation as to the characteristics of the mutants handed over to him, 
and I consequently got the impression that he did not intend to: 
use them for special investigations (cfr. his own remark, p. 321: 
“without it being my intention to examine problems regarding this. 
organism which has already been so diligently investigated from 
many quarters’). If I had had the sligtest idea of the fact that he 
was going to use the cultures for investigation [ should only have 
been too glad to give him all necessary information and also to: 
provide him with additional stocks indispensable for the work. 
Among the cultures mentioned was also a bottle containing the 
combination which is used more extensively than any other in 
every day experimental work, viz., the so called Star Dichaete 
stock. Star is a dominant in the Il, Dichaete a dominant in the III 
chromosome (at 38,5). Both are lethal when homozygous. The 
stock is therefore carried on by mating together in each generation 
Star Dichaete individuals. In the following generation Star‘and not- 
Star, Dichaete and not-Dichaete individuals are accordingly obtained, 
both in the ratio 2 : 1, since the homozygous Star flies as well as. 
the homozygous Dichaete ones all die. The somatic. and genetic 
peculiarities of the Dichaete mutation have on several occasions. 
been described by different workers (see for instance the descrip- 

