470 



SCIENCE 



[N. S. Vol. LIV. No. 1402 



basic ration made of 10 per cent, pure casein, 

 6 per cent, sea salt and 84 per cent, -white 

 flour. The rats were allowed to eat this ad 

 libitum, and were supplied with ordinary tap 

 water in addition. At the end of the thirty- 

 second day butter fat was added to the ration 

 to the estent of 1 gram per rat per day. The 

 experiment lasted 65 days. In the above ex- 

 periment, two rats, both males and weighing 

 65 grams each, and of the same litter, were 

 taken and fed this diet. At the end of the 

 65 days the rat getting the barley with 0.5 

 per cent. PjO^ weighed 108 grams, whereas 

 the one getting barley containing 1.06 per 

 cent. PjOj weighed 117 grams. This differ- 

 ence of 9 grams is small, and yet, owing to 

 the exact manner in which the experiment 

 was performed and the fact that the rats were 

 of the same sex, size and litter, this small dif- 

 ference is significant. 



In the experiment with oats two female rats 

 of the same litter were taken. These rats 

 were practically the same weight. In fact 

 they were of exactly the same weight (55 

 grams) on the second day of the experiment. 

 At the end of 65 days the rat receiving oats 

 with 0.53 per cent. PjOj weighed 86 grams 

 and the rat receiving oats containing 1.1 per 

 cent. PoOj weighed 97 grams. It may be re- 

 marked that the experiments with female rats 

 are not always quite as uniform as those with 

 male rats, but these female rats showed no 

 peculiarities in the growth curves. These ex- 

 periments are in harmony with those of a 

 number of workers and show that the vita- 

 mine content of milled grains is proportional 

 to the content in PjOg. In the case of milled 

 grains, however, the variation in PjO^ is due 

 to its partial removal in milling, whereas in 

 experiments recorded in the present paper the 

 variation is due to the amount of available 

 phosphoric acid in the soil. Since butter fat 

 was fed uniformly throughout the last haK 

 of the experiment, the difference in growth of 

 the rats is due to difference in vitamine B. 

 J. F. McClendon, 

 A. C. Henry 



UNiVEKSiTy or Minnesota 



MOLD HYPH.S; IN SUGAR AND SOIL COMPARED 

 WITH ROOT HAIRS 



To compare sugar with soil as a place for 

 growing molds may at first sight be revolu- 

 tionary, but to one who has studied molds in 

 soil, the first glimpse of a moldy sample of 

 sugar under the microscope compels the com- 

 parison put forward in the title of this paper. 

 Mold hyphse as seen in foods such as sugar 

 and in soil strikingly resemble root-hairs as 

 they develop in earth. Hyphse of fungi and 

 root-hairs are analogous structures. Both be- 

 long to the vegetative phase of a plant's life 

 cycle. Both are turgid, thin-walled cells. The 

 elongating hypha pushes itself between sugar 

 crystals or between soil particles in the same 

 fashion as the elongating root-hair progresses 

 in the soil. The elongating hypha, like the 

 root-hair, is a feeding and growing portion of 

 a plant, which is submerged in a substratum. 

 The hyphal tip, as is commonly understood 

 of the apex of a root-hair, follows between 

 the sugar crystals or soil particles along the 

 path offering the fewest obstacles. Such a 

 path or course is at best winding, irregular, 

 now wide and again extremely narrow. The 

 mold hypha under suitable conditions grows 

 between the faces of the sugar crystals or soil 

 particles. As would the root-hair, it forces 

 its way into a narrow passage, its shape con- 

 forming to the space discovered. There may 

 be a bulge on one surface of the hypha and a 

 flattened area on the opposite surface, all de- 

 pending on the space available for expansion. 

 Attracted by the films of water and available 

 solutes adhering to the sugar crystal or to the 

 soil particle, the mold hypha grows over the 

 face of a particle, conforming to the irregu- 

 larities in the surface of the object. 



It is impossible to separate these bits of 

 mold hyphse from the respective sugar crystals 

 or soil particles in conjunction with which 

 they are growing. It is commonly known that 

 a separation of soil particles from root hairs, 

 which are much grosser units than segments 

 of mold hyphse, is impossible without injury 

 to the root-hairs. 



