494 



SCIENCE 



[N. S. Vol. XXVIII. No. 719 



at Boydton field tests which shall be compar- 

 able to these wire-basket experiments. The 

 main crops to be grown are com and wheat. 

 Frank T. Dillingham 

 BussET Institution, 

 HaevabC Univeesitt, 

 April, 1908 



SUDAN m. DEPOSITED IN THE EGG AND 

 TRANSMITTED TO THE CHICK 



In repeating the experiments reported by 

 Dr. Oscar Riddle' in Science, June 19, 1908, 

 p. 945, for the purpose of demonstration be- 

 fore the third session of the Graduate School 

 of Agriculture of the United States, held 

 July 6-30, 1908, at Cornell University, the 

 results obtained by Dr. Riddle were con- 

 firmed; i. e., Sudan III. fed to hens during 

 the laying period stained red the layers of 

 yolk deposited during the feeding of the Su- 

 dan. The amount of the stain used was much 

 greater (20 to 25 milligrams at a dose) than 

 Dr. Riddle for his special purpose found de- 

 sirable, hence the yolks were strikingly col- 

 ored, and always in concentric layers. Even 

 when all the food eaten by the hen during 

 the entire twenty-four hours was mixed with 

 Sudan, the layers of the yolk were marked.^ 



^Riddle's paper was presented at the zoological 

 meetings during convocation week at Chicago, 

 1907-8. He kindly gave to the authors person- 

 ally the technique necessary for obtaining the 

 colored eggs. 



= If any of the readers of Science desire to 

 experiment with Sudan III. the following hints 

 may be of service: Sudan III. may be purchased 

 of any dealer in microscopic supplies, e. g., the 

 Bausch and Lomb Optical Company, Rochester, 

 N. Y. It is practically tasteless and the dry 

 powder may be mixed with the food or it may be 

 dissolved in olive oil and that mixed with the 

 food. The dose is small (for a hen, 3 to 25 milli- 

 grams). The larger doses give more brilliant 

 coloration. Water, glycerin and formalin do not 

 dissolve either fat or Sudan III., hence watery 

 solutions of glycerin and formalin are good pre- 

 servatives of tissues containing the stained fat. 

 The most satisfactory preservative found both for 

 the eggs and for the entire animals containing 

 colored fat is 5 per cent, formaldehyde. (Strong 

 formalin 10 parts, water 70 parts.) Eggs are 

 best prepared by boiling 15 to 20 minutes, then 



In order to carry the investigation a step 

 farther and to answer the question whether 

 this coloring matter could be carried over to 

 the- chick, some of the " red eggs " were in- 

 cubated, with following results: 



1. As the yolk softened during the pro- 

 cesses of growth of the embryo the layered 

 mass became homogeneous and of a uni- 

 form pink. This was marked from the third 

 day onward. For the first ten days the trans- 

 parent embryo showed no sign of the color. 



2. As soon as the developing chick began 

 to deposit fat, at the seventeenth day of incu- 

 bation, a minute mass of fat lying in the 

 loose connective tissue between the leg and 

 the abdomen was found with the character- 

 istic pink color which depositing fat takes 

 in adults fed with this stain. At this time 

 the egg mass is of a nearly uniform dark red 

 and almost enclosed within the body. 



3. At hatching and several days thereafter 

 the pink fat increased in amount, extending 

 along the side of the sternum, the neck and 

 head and finally appearing on either side of 

 the back in the pelvic region. At the same 

 time the yolk was losing its red color. 



4. It was hoped that the peculiar fat of 

 nerve fibers might take up some of this stain 

 in the period during which myelinization is 

 rapidly proceeding; but the nerve tracts 

 showed only their usual glistening white. 



To briefly summarize: 



1. The specific fat stain, Sudan III., colors 

 the fat laid down in the living hen and in the 

 fatty portions of the yolk while the feeding 

 experiments are in progress, and thus serves 

 to give exact data concerning the time and 

 amount of deposit. 



2. The eggs so colored hatch, and the chick 

 utilizing the yolk as food, produces fat in its 

 own body colored as in the adult, showing in 

 the most striking manner the transmission of 

 a specific and unusual or foreign substance 



the shell is removed from the large end and the 

 white and yolk cut ofif in thin slices, holding the 

 egg and knife under water. Sections through the 

 germinal disk are the most instructive. For 

 permanent support and preservation of the pre- 

 pared eggs glycerin jelly has been found satis- 

 factory. 



