640 



NA TURE 



[October 27, 1904 



ences. Dr. Fleming also proposes the name " kumascopes " 

 for all forms of Hertz wave detectors, but it is not a very 

 pleasant sounding term. 



Telegraphy over wires was not neglected by the congress, 

 and Dr. Kennelly gave both an excellent theoretical paper 

 on the transmission speed over submarine telegraph cables, 

 and a practical one on high frequency telephonic circuit 

 tests. To test the telephone circuit for effectiveness a known 

 sinusoidal E.M.F. is applied, and the corresponding received 

 current strength is measured ; the ratio of these quantities 

 Dr. Kennelly calls the " receiving end impedance " of the 

 circuit at the frequency used (600 ~ in the tests). If this 

 impedance exceeds a certain value, then the circuit will be 

 defective or inoperative. The interesting part of the 

 apparatus is that used for the measurement of the received 

 current ; this is accomplished by passing it through a small 

 platinum wire (Fessenden barretter), which it heats, and 

 the change in its resistance is measured. 



By this means, using a 3 micron wire, 23 microamperes 

 can be measured, and with a 1-7 micron wire in vacuo 

 3 or 4 microamperes is said to be measurable. For practical 

 tests on telephone switchboards the use of a sensitive re- 

 flecting galvanometer, which the above arrangement in- 

 volves, is not very convenient, so the change in resistance 

 of the platinum wire is observed by putting it in series with 

 a sensitive milliameter and cell. A complete portable 

 apparatus of this kind was described, with which one scale- 

 division change in deflection of the Weston milliameter 

 corresponded to 1-4 milliamperes of superposed alternating 

 current. Curves are given in the paper showing tests of 

 different lengths of cables. 



The improvement of telephonic communication by in- 

 creasing the self-induction of the circuits is receiving con- 

 siderable attention in the States, and Dr. Hammond Hayes 

 gave some most striking curves illustrating the reduction 

 in attenuation which has been produced by the use of 

 uniformly spaced loading coils on long circuits. The im- 

 provement is verv much more marked in the case of cables 

 than air wires. The most striking results are those obtained 

 with a standard telephone cable which was heavily loaded 

 so that the added inductance amounted to about 06 henry 

 per mile. In this case, from Dr. Hayes's curves the received 

 current was reduced to about 5 per cent, of the transmitted 

 value at a distance of fifty miles with the cable unloaded, 

 whereas with the loaded cable the received current was 

 7 per cent. Further, the great importance of terminal re- 

 flection where the loaded cable joins the transmitting and 

 receiving apparatus is most marked, as by reducing the 

 self-induction of the end loading coils so as to taper it off 

 and avoid a sudden change in the self-induction the received 

 current was increased to about iS per cent. 



It is also very interesting to note how the curves cross 

 one another, so that short lengths of cable give better 

 results without loading, whereas the cable with loading 

 and terminal taper above six miles long produces less 

 attenuation than the unloaded cable, the advantage in favour 

 of the loaded cable increasing with its length. 



There were many other papers of great scientific interest ; 

 among these may be mentioned Dr. Pender's paper on the 

 magnetic effect of moving charges, which clears up many 

 of the differences which existed between his results and 

 those obtained by Cr^mieu, and suggests several other 

 interesting problems ; Prof. Wilson on condensation nuclei ; 

 two papers on the theory of conduction by Prof. Drude and 

 Prof. Richards; and Prof. .Arrhenius's paper on the electric 

 charge of the sun. 



In conclusion, it must be said that the congress was a 

 complete success, perhaps more so than might have been 

 expected, considering the great distance many of the 

 members had to travel to attend its meetings, and this was 

 greatly due to the indefitigable energy of its organisers, 

 and especially to Prof. Ellhu Thomson, the president. Dr. 

 Kennelly, and Mr. Weaver. The attendance at the meet- 

 ings was good, and if the discussions were not always as 

 full as could be wished, this was not from lack of interest 

 in the papers, but from lack of time. All the foreign 

 members of the congress, irrespective of nationality, were 

 received and entertained in the most hearty manner by their 

 .■\merican confreres, fully bearing out the world-wide 

 reputation that -America has for hospitality. 



W. DUDDELL. 



NO. 1826, VOL. 70I 



PHYSIOLOGICAL CHEMISTRY IN THE 

 UNIVERSITY OF GLASGOW. 



T^OWARDS the close of his introductory lecture to the 

 course of physiology in the University of Glasgow on 

 October 13, Prof. McKendrick said : — 



I think there can be little doubt that the next great 

 advance in physiology will be from the side of physiological 

 chemistry. The phenomena of vital activity depend on 

 chemical processes in which there are either the building up 

 of complex substances by the union of simpler ones, or the 

 decomposition of complex bodies into simpler ones — in other 

 vvords, processes that are of a synthetical or of an analytical 

 nature. These chemical phenomena lead, on the one hand, 

 either to the locking up, or, on the other, to the liberation 

 of energy, and the energy in a living being may appear as 

 mechanical motion, heat, electricity, and to some small 

 extent, and in special cases, as light and sound. During 

 the last sixty years many of the physical phenomena of the 

 living being have been investigated by special methods. 

 It seems to me that we cannot expect much more from the 

 application of the graphic method of registration, nor from 

 the examination of the phenomena of electrical action in 

 living tissues. The microscope and the methods of histo- 

 logical research have left little to be desired as to our know- 

 ledge of the structure of the elementary tissues and the 

 structure of organs. A new departure must be made. No 

 method of research seems so inviting or so promising as 

 the rigid and methodical investigation of the chemical 

 phenomena happening in living matter. 



Hence the extreme importance of the chemist and the 

 physiologist working hand in hand for the future advance- 

 ment of physiological knowledge. .At one time it was sup 

 posed that, the chemical phenomena happening in the living 

 body were of a different order from those occurring in dead 

 matter. In 1824, however, Wohler pointed to the first 

 example of a synthetical process discovered within the 

 animal organism. He showed that when benzoic acid is 

 introduced into the stomach it appears as hippuric acid in 

 one of the excretions, after coupling, probably in the liver, 

 with amido-acetic acid or glycocoll. About the same time 

 Hennell effected the synthesis of alcohol, and Wohler formed 

 urea from ammonium cyanate. As urea was then known 

 only as a product of the animal organism, its synthesis from 

 inorganic substances, and in the laboratory, was a feat of 

 the first importance. This synthesis was the precursor of 

 many others, so that we have now, at the lowest estimate, 

 between two and three hundred chemical substances found 

 in plant and animal tissues that can also be built up 

 synthetically by the organic chemist. Year by year we are 

 adding to this extensive list. Some of these syntheses are 

 striking examples of the knowledge and skill of the chemists 

 of the present day. Such, to mention one brilliant series, 

 are the artificial productions of the sugars by the labours 

 of Fischer and his pupils. Take, again, the formation of 

 the highly complex bodv camphor, realised by Komppa and 

 Vorliinder. It may not be a day-dream if we contemplate 

 the time when even the starches, fats, and proteids we use 

 in our food may also be artificially formed. Physiological 

 chemists have also done much in the way of studying the 

 chemical changes happening to a substance during its. 

 passage through the body, but this is a much more difficult 

 branch of physiological chemistry than even the synthetic 

 production of organic bodies. 



.And yet we are far from solving the mystery of what we 

 may call vital chemistry. When we think, for example, of 

 the synthetical processes by which the chemist construct.?, 

 complex bodies hitherto only found in the tissues of plants 

 and animals, the question naturally occurs : how does 

 nature produce these complicated molecules without the use 

 of strong reagents and high temperatures? This aspect of 

 the question has been well discussed by my friend Prof. 

 R. Meldola, first, in an address as president of the chemical 

 section of the British .Association at the Ipswich meeting 

 in 1885. and, second, in an important work, soon to be 

 published, the proof sheets of which he has kindly allowed 

 me to peruse, entitled " The Chemical Synthesis of X'ital 

 Products." It is clear from a study of the examples given 

 by Prof. Meldola that the synthetical processes worked out 

 by the chemist in his laboratory are quite unlike those occur- 

 ring in plant and animal tissues, and vet the result is the 



