446 



NATURE 



\A^arch 22, 1877 



service in many ways. The volumes altogether are very 

 readable, and throughout the statements are usually 

 reliable. Should a second edition be required it might 

 possibly be improved by the addition of a " table of 

 contents." W. H. W. 



THE GERM THEORY 



The Germ Theory Applied to the Explanation of the 

 Phenomena of Disease. " The Specific Fevers^ By 

 T. Maclagan, M.D. (London : Macmillan and Co., 

 1876.) 



IN his-prefac2 the author states that "one object which 

 he has in vit"^ is to rescue the germ theory of dis- 

 ease from a false and misleading position, and to give to 

 it its true and legitimate standing as a pathological ques- 

 tion." The subject discussed is whether the propagation 

 of germs in the system can produce specific fevers. He 

 believes it can, and assumes that all contagia are living 

 organisms, probably albuminous, reproducing their kind, 

 living for a considerable period, speedily perishing when 

 freely exposed to the atmosphere, and so minute as to 

 elude the highest powers of the microscope. 



If, however, the particles in sheep-pox, small-pox, and 

 vaccine, be the infecting matter, they are easily seen by 

 the microscope, and ought therefore to be found in the 

 blood, but such is not the case. 



Dr. Maclagan holds that "all microzymes are not con- 

 tagia, but all contagia may be microzymes." The fact 

 that the contagia fluids are most potent when fresh, and 

 that their virulence diminishes as bacteria increase in 

 them is explained by saying that disease-germs are more 

 minute organisms than bacteria, and are the food on 

 which bacteria live. According to this view, bacteria not 

 only do not constitute infection, but destroy it. 



Dr. Maclagan says " that the chief action of an or- 

 ganism on its environment is the consumption of nitro- 

 gen and water. A disease-germ is a parasite, and requires 

 a special nidus as well as nitrogen and water ; the para- 

 site finds a something in its nidus — the second factor — 

 the parasite being the first. Without this second factor 

 no bad result follows the reception of the contagium." 

 Different periods of incubation are accounted for by the 

 varying amount of the second factor and the number of 

 germs imbibed ; incubation itself by germ-grov/th and 

 reproduction ; and the onset of the symptoms by the 

 germs becoming mature. 



The consumption of nitrogen by the contagium particles 

 causes wasting of the tissues, i.e., the organisms eat the 

 albumen intended to nourish the body. They also drink 

 largely of water from the liquor sanguinis, which, being 

 rich in soda, explains why soda-salts are often absent 

 from the excretions during fever. The same retention of 

 soda-salts, however, often happens in acute pneumonia, 

 which has no relation to infectious disease. 



Increased elimination of urea is explained thus : — 

 " The increased consumption of liquor sanguinis by the 

 contagium particles leads to increased formation of re- 

 trogressive albumen and of urea," It seems by this that 

 contagium particles have livers and kidneys, and excrete 

 urea. Diminished excretion of urea is held as " due to 

 consumption by the contagium particles of the water re- 

 quisite to enable the kidneys to perform their excretory 



function." What then, we ask, becomes of the water 

 consumed by the contagium particles ? Do their kidneys 

 excrete urea in excess with limited water, while those of 

 the patient are unable to do so ? or do the contagium par- 

 ticles not consume water when the urea is increased as 

 well as when it is diminished ? In fever the quantity of 

 water drank by the patients is very great, but that, accord- 

 ing to Dr. Maclagan, is because the quantity of contagium 

 particles is also very great. We find, however, the same 

 symptoms in symptomatic fevers, with no contagium 

 particles present, and we have great difficulty in believing 

 that ultra-microscopic organisms in a person's blood could 

 consume several tumblerfuls of water in twenty-four 

 hours. 



The heat of specific fevers is partly ascribed to the 

 propagation of the contagium causing increased con- 

 sumption of tissue. But increase of living matter causes 

 the disappearance of heat, not its production. Again, the 

 author states that the fecundation of the organisms may 

 be accompanied by an elevation of temperature analogous 

 to that which occurs under similar circumstances in other 

 organisms. 



As regards treatment, at page 163 the following occurs : 

 " If we were to bleed, to purge, to give antimony to, or even 

 simply to withhold food and water from, all the cases of 

 typhus and enteric fever which occur, there can be no 

 doubt that we should find the mortality from those 

 diseases greatly increased." Dr. -Maclagan is right here, 

 for by simply withholding food and water, there can be 

 no doubt that he would greatly increase the mortality by 

 starvmg his patients to death. He, however, believes that 

 fever patients should be supplied with nitrogen and water 

 to compensate for what the organisms consume. 



The cessation of the fever and its specificity are attri- 

 buted — the first, to the organisms, as parasites, requiring a 

 special nidus which contains a suitable pabulum, and 

 when the latter is exhausted the fever ceases ; the second, 

 to a local lesion in the nidus, which is the part where 

 fecundation of the organism takes place. In small pox 

 this nidtcs and lesion is in the skin, in typhoid in the 

 bowels, and so on. It is well-known, however, that many 

 medicines act on special parts of the body, and yet we 

 do not think of calling them parasites which require a 

 special nidus. The author gives many other plausible, 

 and some very unusual explanations of febrile phenomena 

 by means of the germ theory, all of which, we believe, are 

 far more clearly and rationally explicable on the physico- 

 chemical theory. The writing of this book must have 

 cost Dr. Maclagan much trouble. We have read it very 

 carefully, and commend the author's honesty in stating 

 his views, but question if the work will go far in realising 

 the object for which it was ostensibly written. 



. OUR BOOK SHELF 



A Manual of Cinchona Cultivation in India. By 

 George King, M. B., F.L.S., Superintendent of the 

 Royal Botanical Garden, Calcutta, and of Cinchona 

 Cultivation in Bengal. (Calcutta, 1876.; 



This manual is another contribution to the numerous 

 books, papers, and articles that have appeared of late 

 years on the subject of cinchona. Varied as these contri- 

 butions have been, and valuable each one in itself, this 

 manual brings together much that is useful, not only on 



