PHYSIOLOGY. 



565 



performed. In some earlier cases taste was not 

 tested, so that as far as the observations of this 

 group of authorities go the result has been con- 

 stant. Mr. Horsley is quoted as representing 

 that in the cases he has operated on in private in 

 which he has afterward tested taste, he has in 

 each case found it lost. These facts are regarded 

 as constituting strong evidence that the sugges- 

 tion of disease was correct, and that all the fibers 

 of taste, at least in most persons, reach the brain 

 by the fifth nerve. The path by which the taste 

 impressions reach the fifth nerve deserves further 

 investigation, but hardly lends itself to experi- 

 mental research. 



Miscellaneous. The results of studies of the 

 effect of marching and carrying of loads, as in 

 military service, upon 5 students of the Kaiser 

 Wilhelm Academic have been published by Prof. 

 Zuntz, of the tloyal Agricultural College, Berlin, 

 and Chief-Surgeon Schomberg. The experiments 

 were made during April, May, June, and July, 

 under stated and uniform regulations, and the 

 condition of the subjects was examined before 

 and after, and sometimes during the march and 

 on days of rest, with reference to all organs 

 and functions likely to be influenced by carrying 

 heavily loaded knapsacks. The tests included 

 sphygmographic tracings, enumeration of blood- 

 corpuscles, estimation of the specific gravity of 

 the blood, reaction of the muscles and nerves, 

 measurements of vital capacity, and records of 

 variations in urinary constituents. A second 

 and more complicated investigation was carried 

 out with two of the students to determine the 

 effect of marches on metabolism. Experiments 

 were also made with lighter weights and with loads 

 of 22, 27, and 31 kilograms. The general condi- 

 tion of the students improved, excessive fat dis- 

 appeared, and the body weight was reduced by 

 from 1.5 to 3.5 kilograms; the cardiac systole 

 was prolonged and the diastole was shortened as 

 the weights carried were increased. The pulse in- 

 creased to 140 and 150 beats a minute, and di- 

 crotism became marked as the duration of the 

 diastole and systole approached equality. 



Among 89 observations the cardiac area of dul- 

 ness showed marked increase in 64, and the he- 

 patic area in 67 instances after march. The 

 increase in the area of dulness was found due 

 to dilatation of the right and not of the left 

 side of the heart, and to be produced by a gen- 

 eral stagnation of the venous circulation. The 

 phenomenon is designated by the authors as 

 " march dilatation of the left side of the heart." 

 Observations on other organs and functions did 

 not produce so interesting and positive results. 

 The specific gravity of the blood increased only 

 by 0.006, and the red blood-corpuscles by 9 per 

 cent, after the heavier march. An apparent in- 

 crease in the white corpuscles was due to poly- 

 nuclear cells being carried into the circulation from 

 the walls of the larger veins in consequence of 

 increased cardiac action; but the blood resumed 

 its normal condition on the day following the 

 march. The vital capacity of the lungs was in- 

 creased up to a certain point by graduated train- 

 ing, but marked diminution occurred in the 

 marches with the heaviest loads, the result being 

 associated with the dilatation of the heart and 

 liver and the venous stagnation already noticed. 

 The increase in frequency of respiration associ- 

 ated with exercise gradually fell to normal dur- 

 ing halts, but when dilatation of the right side 

 of the heart had become well marked the in- 

 crease remained as high as 40 per cent, above 

 normal even after a halt of thirty minutes. The 

 heat production of the work done in marching 



was estimated to be enough to raise the bodily 

 temperature 1 C. in 8.7 minutes. fc'rom ex- 

 periments on the influence of marches on nerv- 

 ous energy-producing material, the authors con- 

 clude that in continuous heavy marching the car- 

 bohydrates consumed in the rations are not suf- 

 ficient to replace the waste; and that a day's 

 rest is required after every three days' marching 

 to enable the blood to recover its normal power. 

 It is understood that the German military au- 

 thorities have accepted the investigators' conclu- 

 sions as authoritative; and the regulations on 

 physical training in Germany are evidently in- 

 spired by them. 



A general review of the results of the researches 

 of Ehrlich and his colleagues and followers on the 

 subject of immunity was given by Prof. W. C. 

 Halliburton in his address at the British Asso- 

 ciation, who said that the power the blood pos- 

 sesses of slaying bacteria was first discovered 

 when the effort was made to grow various kinds 

 of bacteria in it, it having been looked upon 

 as probable that the blood would prove a 

 suitable medium for the parasite. Instead, the 

 blood was found in some instances to have ex- 

 actly the opposite effect. The chemical charac- 

 ters of the substances which kill the bacteria 

 were not fully known; but absence of knowledge 

 on this particular point had not prevented im- 

 portant discoveries from being made. So far as 

 was known at present, the substances in question 

 were proteid in nature. The bactericidal pow- 

 ers of blood were destroyed by heating it for an 

 hour to 56 C. Whether the substances were 

 enzymes was disputed; so also was the question 

 whether they are derived from the leucocytes. 

 The substances are sometimes called alexins, but 

 the more usual name now applied to them is 

 bacterio-lysins. Closely allied to the bactericidal 

 power of blood or blood-serum, was its globu- 

 licidal power, by which it is meant that the blood- 

 serum of one animal has the power of dissolving 

 the red blood-corpuscles of another species. The 

 bactericidal power of the blood was closely re- 

 lated to its alkalinity and increased with it. 

 Normal blood possessed a certain amount of sub- 

 stances which were inimical to the life of our 

 bacterial foes. When a person gets " run down." 

 as it is called, and is weak against attacks of dis- 

 ease, it is coincident with a diminution in the 

 bactericidal power of his blood. But even a per- 

 fectly healthy person has not an unlimited supply 

 of bacterio-lysin, and if the bacteria are suffi- 

 ciently numerous, he will fall a victim to the 

 disease they produce. But in the struggle he 

 will produce more and more bacterio-lysin, and 

 if he gets well it means that the bacteria are 

 finally vanquished, and his blood remains rich 

 in the peculiar bacterio-lysin he has produced, 

 and so will render him immune to further at- 

 tacks from that particular species of bacterium. 

 Every bacterium seems to cause the development 

 of a specific bacterio-lysin. Immunity can more 

 conveniently be produced gradually in animals, 

 and this applies not only to the bacteria, but also 

 to the toxins they form. 



In the hypothesis by which he seeks to explain 

 the phenomena of immunity, Ehrlich supposes 

 that the toxins are capable of uniting Avith the 

 protoplasm of living cells by possessing groups 

 of atoms like those by which nutritive proteids 

 are united to cells during normal assimilation, 

 and which he terms heptophor groups; while 

 the groups to which these are. attached in the 

 cells are termed receptor groups. The introduc- 

 tion of a toxin stimulates an excessive produc- 

 tion of receptors, which are finally thrown out 



