224 



SCIENCE 



[N. S. Vol. LIV. No. 1393 



QUOTATIONS 



DYES FOR BACTERIOLOGY 



Bacteriologists in this country and in the 

 United States of America are anxious about 

 the supply of chemical dyes used in their work. 

 Animal tissues and the microbes which may 

 infest them, as seen under the microscope, 

 present to the eye an almost uniform appear- 

 ance of pale translucency. A skilled treatment 

 with dyes and mordants reveals the otherwise 

 invisible differences of structure and com- 

 position. Particular cells and granules, bac- 

 teria and spores, have affinities for particular 

 stains, and betray their presence by the colors 

 they absorb. The presence, the quality, and 

 even the phase of an infection or of a morbid 

 state are thus detected, and the processes are 

 a necessary part of research, diagnosis, and 

 treatment. But the reactions are delicate, 

 and their value depends on a high purity 

 and standardization of the reagents employed. 

 The materials are almost entirely the aniline 

 dyes used in textiles. Before the war Griibler 

 in Germany had examined these and selected 

 those that might be of use to biologists. The 

 total bulk of the trade is very small, and the 

 German manufacturer had taken so much 

 trouble to standardize his products and secure 

 their purity that he had a practical monopoly 

 and was able to charge a high but legitimate 

 price. When the war came, in 1914, a few 

 fortunate institutions had in hand a stock of 

 the Griibler reagents sufficient to meet their 

 wants. But the greater number of biologists 

 were soon in diificulties. Here and in the 

 United States several manufacturers, partly 

 from patriotic motives and partly from the 

 attraction of the great difference in price 

 between the crude textile dyes and the micro- 

 scope stains, began to supply the demand. 

 There is no reason to suppose that their out- 

 put was inferior to the German products. But 

 it varied from manufacturer to manufacturer 

 in its precise qualities. The users got results 

 which were not exactly comparable with those 

 obtained from the Griibler products or with 

 each other. The total demand, moreover, is 

 so small in bulk that it is hardly worth dis- 



tributing. The situation has given rise here 

 and in America to a desire for the free im- 

 portation of German bacteriological stains, 

 on the one hand, and, on the other, to fresh 

 efforts to maintain national independence in 

 this branch of scientific work. The Society 

 of American Bacteriologists is endeavoring 

 to secure cooperation in determining on a 

 reliable standard brand of each kind of stain, 

 and in discouraging the marketing of variants. 

 A similar course in this country would be 

 very convenient. — The London Times. 



SPECIAL ARTICLES 



THE SECOND-YEAR RECORD OF BIRDS WHICH 

 DID AND WHICH DID NOT LAY DURING 

 INDIVIDUAL MONTHS OF THE PUL- 

 LET YEAR 



The egg output of the commercial poultry 

 plant is due in part to birds in their first 

 and in part to birds in their second year. 

 At some time during the first year the number 

 of pullets is reduced to the number which is 

 to be retained as hens during the second 

 year. 



It would be of obvious advantage if the 

 birds sold from the flock as pullets could be 

 those which if retained would make the poorest 

 record in their second year. If the birds 

 destined to be the highest producers in the 

 second year could be selected on the basis of 

 some criterion recognizable in the first year, 

 it should be possible to raise the average pro- 

 duction of the flock as a whole by increasing 

 the average production of the hens. 



In the course of a general investigation of 

 the problem of the prediction of the egg pro- 

 duction of the domestic fowl from the records 

 of short periods, we have availed ourselves 

 of the opportunity of considering the relation- 

 ship between first and second year laying 

 activity presented by the data of the Vine- 

 land International Egg Laying and Breed- 

 ing Contest. As one phase of this work^ we 

 have sought to determine to what extent the 

 simple criterion of laying versus not laying 

 in any month of the first year may be used 



1 Other phases of the investigations will be re- 

 ported in detail elsewhere. 



