760 



PHYSIOLOGY. 



while the lungs are invariably situated on the 

 ventral side, of the intestinal canal. If these 

 two organs were homologous, the dorsal organ, 

 to be transformed into a ventral, must make its 

 passage around the oesophagus. The assump- 

 tion, however, of either a right-sided or a left- 

 sided passage, or of a double division of the 

 swimming-bladder, each of which has wan- 

 dered downward on one side, there to form 

 two halves of the lungs, is a notion that labors 

 under difficulties and contradictions. A very 

 strong argument for regarding the swimming- 

 bladder and the lungs as completely heterolo- 

 gous organs is afforded by those fishes which 

 possess two bladders, one above and one be- 

 low the intestinal canal a phenomenon which 

 would be impossible if these bladders were 

 homologous. Some fishes also possess only the 

 ventral swimming-bladder. Support to the 

 author's view was also afforded by the fact 

 that even in the case of mammalia, in which 

 the ventral protrusion of the intestinal tube 

 has developed into lungs, remains of the dorsal 

 swimming-bladder are presented in a rudiment- 

 ary form. 



Digestion. Prof. Ewald, in accounting for 

 the second noise in swallowing, controverts 

 the explanation of the phenomena by Kro- 

 necker and Meltzer, that it is produced by the 

 contraction of the lower part of the oesophagus 

 when the bit swallowed is pressed into the car- 

 diac orifice. From observations on sound and 

 diseased persons, and on animals, the author 

 had arrived at the conclusion that the sound 

 was generated by the entrance of air into the 

 cardiac orifice. Both in the case of swallow- 

 ing anything, and of not swallowing anything, 

 whether it were altogether empty swallowing 

 or only saliva trickling down, air penetrated 

 into the lower part of the oesophagus. Air 

 might, however, likewise penetrate from the 

 stomach upward. In proof of the correctness 

 of this interpretation were, first, the fact that 

 the phenomenon was absent when water was 

 carefully drunk; and, second, that the noise 

 was sometimes heard without any bit being 

 swallowed. Kronecker and Meltzer had said 

 that the piece swallowed stayed for six seconds 

 before the cardiac orifice till it got pressed into 

 it. This did not seem to be the case, but the 

 piece swallowed passed continuously into the 

 cardiac orifice, and finally the co-entering air 

 was pressed, with emission of noise, through the 

 sphincter tnto the stomach. 



Wenz and Kuhne have investigated anew 

 the question of the digestion of albumen in 

 the intestine. The results of their experi- 

 ments indicated but slight peptonizing power. 

 This conclusion agrees with those which were 

 reached by Ozerny and Latschenberger, Mark- 

 wald and Demaut, but is contradictory of those 

 reached by a larger number of observers. 



According to Klenze, the digestibility of 

 cheese depends a good deal on its physical 

 properties. All fat cheeses are dissolved or 

 digested with great rapidity, because the mole- 



cules of caseine are separated only by the fat, 

 and so the solvent juice can attack a large sur- 

 face of the cheese at one time. Whether the 

 cheese be hard or soft does not appear to mat- 

 ter, and there is no connection between the 

 digestibility and the percentage of water pres- 

 ent in the cheese. The degree of ripeness and 

 the amount of fat have, however, considerable 

 influence, for both these conditions render the 

 cheese more friable, and so allow of intimate 

 contact of the juice. 



Drs. N". A. Randolph and A. E. Roussel have 

 made a study, with pigs, of the nutritive value 

 of branny foods with a view of testing the va- 

 lidity of the belief which some dietarians carry 

 into their practice, that " Graham bread " or 

 bread from whole wheat is the most whole- 

 some and the most nutritious. They have sum- 

 marized their conclusions as follows : The car- 

 bo-hydrates of bran are digested by man to but 

 a slight degree. The nutritive salts of the 

 wheat-grain are contained chiefly in the bran, 

 and therefore, when bread is eaten to the ex- 

 clusion of other foods, the kinds of bread which 

 contain those elements are the more valuable. 

 When, however, as is usually the case, bread is 

 used as an adjunct to other foods which con- 

 tain the inorganic nutritive elements, a white 

 bread offers, weight for weight, more availa- 

 ble food than does one containing bran. By 

 far the major portion of the gluten of wheat 

 exists in the central four fifths of the grain, en- 

 tirely independent of the fourth bran layer 

 (the so-called " gluten-cells "). Further, the 

 cells last named, even when thoroughly cooked, 

 are little if at all affected by passage through 

 the digestive tract of the healthy adult. In an 

 ordinary mixed diet, the retention of bran in 

 flour is a false economy, as its presence so 

 quickens peristaltic action as to prevent the 

 complete digestion and absorption, not only of 

 the proteids present in the branny food, but 

 also of other food -stuffs ingested at the same 

 time. Inasmuch as in the bran of wheat, as 

 ordinarily roughly removed, there is adherent 

 a noteworthy amount of the true gluten of the 

 endosperm, any process which in the produc- 

 tion of wheaten flower should remove simply 

 the three cortical protective layers of the grain, 

 would yield a flour at once cheaper and more 

 nutritious than that ordinarily used. 



J. R. Walker, dental surgeon, has drawn 

 some interesting conclusions from his observa- 

 tions of the conditions of the teeth of the peo- 

 ple living in a region near the Gulf of Mexico, 

 where their food and the water are destitute 

 of, or only scantily provided with, lime con- 

 stituents. The constitutions of the natives of 

 the district seem to have become adapted to 

 the deficiency in mineral elements, and have 

 acquired the power of appropriating from the 

 meager supply furnished them enough to pro- 

 duce fairly good teeth. But residents not na- 

 tive, coming from regions where calcic ele- 

 ments are more abundant, are not able to as- 

 similate enough mineral salts to keep their 



