670 



PHYSIOLOGY. 



of excitation the rhythm of muscular response 

 is maintained at a fairly uniform rate of about 

 10 per second." Therefore, in the light of their 

 research, the authors conclude either that the 

 rhythm of volitional impulses proceeding from 

 cerebral motor areas has an average rate of 10 

 or 12 per second, or that it has some unknown 

 higher rate transmuted into one of 10 or 12 per 

 second by the activity of the motor cells of the 

 anterior cornua of the spinal cord. 



The observations of Harris on the muscular 

 rhythm of voluntary tetanus in man, confirm- 

 ing in the main those of Schafer and Griffith, 

 indicate that the thrill is due to a muscular vibra- 

 tion, the rate of which varies from 10 to 15 vibra- 

 tions in a second, with an average of about 12 

 or 13. 



In a long series of experiments to determine 

 whether any one alone of the food stuffs proteids, 

 fats, or carbohydrates can be regarded as the 

 source of muscular energy, Prof. Zuntz found 

 that a dog could be fed and nourished quite well 

 on either, and that each one of them suffices to 

 provide the energy necessary for the work done 

 by the muscles. Comparative experiments to 

 determine whether any one alone of the three 

 food stuffs can be most advantageously employed 

 for supplying this energy have not as yet led to 

 any decisive result. 



In a communication to the Royal Society, Dr. 

 Vaughan Harley first gave the chemical reasons 

 that led him to believe that sugar is the princi- 

 pal factor in the production of muscular energy. 

 He then went on to prove that it could be ex- 

 perimentally demonstrated that the addition of 

 large quantities of sugar to the diet causes an 

 increased capability of doing muscular work. By 

 means of the ergograph it was possible to esti- 

 mate the amount of work accomplished under 

 various circumstances by the middle finger of 

 each hand as in raising weights of Band 4 kilo- 

 grammes. The total height to which the weight 

 was lifted, being multiplied by the weight used, 

 expressed in kilogram metres the amount of work 

 accomplished. The first step was to ascertain 

 the value of sugar in the production of muscular 

 work when taken alone. During a twenty-four 

 hours' fast, on one day, water alone was drunk; 

 on another day, 500 grammes of sugar were taken 

 in an equal quantity of water. It was then found 

 that the sugar not only prolonged the time be- 

 fore fatigue occurred, but caused an increase of 

 from 01 to 76 per cent, in the muscular work 

 done. The effect of sugar added to the meals 

 in producing muscle energy was found to be so 

 great that 200 grammes added to a small meal 

 increased the total amount of work done from 6 to 

 39 per cent. Sugar (250 grammes) was next added 

 to a large mixed meal, when it was found to in- 

 crease the amount of work done from 8 to 16 per 

 cent., and. further, to increase the resistance 

 against fatigue. As a concluding experiment, 

 250 grammes of sugar was added to the meals of 

 a full diet day. causing the work done during a 

 period of eight hours to be increased from 22 to 

 36 per cent. 



Miscellaneous. It has been noticed by vari- 

 ous observers, says Prof. E. A. Schafer, in his 

 presidential address before the physiological sec- 

 tion of the British Association, that in certain 

 specialized animal cells the protoplasm shows a 



tendency to radiate from or converge toward a 

 particular point. On further investigation this 

 point proved to be a minute particle. The ob- 

 servation was found afterward to hold good for 

 other and yet other cells, until at the present 

 time it is believed that such a particle exists in 

 every cell of the animal or plant body. It hence 

 appears that the whole cell is not of a uniform 

 nature, since there is this one point within it that 

 exerts a special attraction upon the rest of the 

 cell substance ; and on this account the particle 

 has come to be termed the " attraction particle." 

 It has been found that one of the most impor- 

 tant phenomena exhibited by the cell hinges upon 

 the behavior of this particle ; it is observed that 

 before a cell or its nucleus divides, this minute 

 attraction particle begins by itself dividing, and 

 it is, in fact, more commonly met with double 

 than single. It is not until the two particles 

 thus produced have evolved, either from them- 

 selves or from the substance of the protoplasm 

 or nucleus, a system of communicating fibers 

 the achromatic spindle that those changes in 

 the nucleus and protoplasm take place which pro- 

 duce the division and multiplication of the cell. 

 This attraction particle, which is also called the 

 central panicle or centrosome, has engaged great 

 interest, and has been the subject of many papers, 

 the latest of which is an elaborate treatise of 

 about 300 pages by Martin Heidenhain. He ex- 

 presses the conclusion that this particle is 

 morphologically, physiologically, and chemically 

 a structure of its own kind; "not merely a sep- 

 arate portion of nucleus or protoplasm, but an 

 organ of the cell with definite functions, and 

 having a definite existence of its own." It is, 

 however, extremely minute. Yet it initiates and 

 directs those processes which result in the multi- 

 plication of the cell, and is therefore concerned 

 in directing the general growth of the individual, 

 and ultimately the propagation of the species. 



The aquatic biological stations, of which many 

 have now been established, are of special value 

 in physiology in that they constitute centers in 

 which the activities of the cell, as exhibited in 

 the lowest organisms, can be carefully investi- 

 gated. Prof. Vernom, of Jena, has remarked 

 that it is on this line that progress in physiology 

 may be anticipated. We have traced all phe- 

 nomena of change in matter, form, and force back 

 to the points where they disappear in the cell : 

 but of what takes place in the muscle cell, the 

 ganglion cell, the lymph cell, the gland cell, we 

 have no conception. Mr. Adam Sedgwick warns 

 students, however, against forming too high an 

 estimate of the form and attributes of the cell, 

 and particularly regarding the part played by it in 

 the modern theory of development. Observers 

 habituated to regard the cell as the anatomical 

 unit sometimes fail to see that instead of cells 

 there are in many situations only nuclei connected 

 by a reticulum of a pale substance, and that, in 

 these situations at least, no proper cells exist. 



In experiments reported by Marie de Mana- 

 ce'ine, dogs from two to four months of age were 

 prevented from sleeping and the physiological 

 and anatomical effects of the treatment were 

 recorded. For these animals, at least, loss of 

 sleep appeared to be much more detrimental 

 than starvation. Dogs that have starved more 

 than twenty days and have lost more than 50 per 



