June i6, 1892] 



NATURE 



149 



extinction of plague is one of enormous difficulty. 

 The materials for such a history must be sought for high 

 and low ; chance allusions in private letters or municipal 

 records will supply links in the chain of evidence for 

 which the writings of the medical authorities of the time 

 may be searched in vain, if indeed there be any medical 

 authorities ; and Dr. Creighton found that for his purposes 

 *' medical books proper are hardly available . . . until the 

 end of the Elizabethan period, . . . and do not begin to be 

 really important . . . until shortly before the date at which " 

 his present labours end. When such evidence as can 

 be found has been found and sifted, there still remains 

 the most intricate problem of all — that of tracing the 

 epidemics recorded to their origin, accounting for their 

 spread, and in some cases explaining why a country 

 should in modern times be spared diseases which 

 scourged it in the Middle Ages. 



No better illustration of these difficulties could be found 

 than is supplied by chapter ii., " Leprosy in Mediaeval 

 Britain." The first point that Dr. Creighton has to make 

 clear is that all the so-called lepers were not really lepers. 

 In extreme cases the word " leprosus " may have been 

 used simply as meaning " beggar or common tramp " ; 

 elsewhere it may have been applied to victims of syphilis, 

 lupus, and so forth. For the sufferers special provision 

 was no doubt made, on a scale due in part to a morbid or 

 mistaken religious sentiment ; but examination of the 

 charters and other documents relating to these charities 

 suggests that, of the supposed foundations for lepers, some 

 were merely refuges for sick and infirm poor, in others 

 provision was made for three or four times as many non- 

 leprous as leprous inmates, while from others, towards the 

 end of the thirteenth century, the lepers were disappear- 

 ing or getting displaced. Finally, the author concludes 

 that the prevalence of true leprosy at any time in England 

 was probably not so great as in the worst provinces of 

 India at the present day ; but, however justifiable scepti- 

 cism as to its supposed ravages may be, that the disease 

 really did prevail can hardly be doubted, and the reasons 

 for doubt are lessened, if a vera causa for its presence 

 can be found. Such a vera causa, compatible with its 

 subsequent disappearance, may be discovered, not in 

 " importation," e.g. by Crusaders— a suggestion Dr. 

 Creighton does not consider worth thinking about — but in 

 the staple diet of the times, a semi-putrid or toxic character 

 of animal food combining with other depressing influences 

 to give rise to leprosy, just as a similar character of bread 

 or porridge gives rise to pellagra. 



We have given the arguments of this chapter some- 

 what in detail, because the criticism which obviously 

 applies to them, applies elsewhere. Considering the un- 

 certainty which surrounds the facts, it is clear that the 

 traditions of the leprosy of the past cannot very materially 

 assist, though they may be explained by, the study of 

 modern leprosy. Similarly, in the case of the plague, to 

 which naturally Dr. Creighton devotes much of his book, 

 to say nothing of that old question, the value of the 

 evidence of the Bills of Mortality, the inquirer is met at 

 once by the great difficulty of knowing when "the plague" 

 which is spoken of as invading out-of-the-way places really 

 was the genuine plague — a point of vital importance, as 

 soon as any etiological questions are raised, and we may 

 here observe that Dr. Creighton writes :— 

 NO. I 181, VOL. 46] 



" In concluding the career of the sweat in England, we 

 may pass from it with the remark that it did not cease until 

 other forms of pestilential fever were ready to take its place. 

 The same explanation remains to be given of the total 

 disappearance of the plague from England after 1666 : it 

 was superseded by pestilential contagious fever, a disease 

 which was its congener, and had been establishing itself 

 more and more steadily from year to year as the con- 

 ditions of living in the towns were passing more and more 

 from the mediasval type to the modern." 



It would be impossible here to enter into the merits or 

 the reverse of all Dr. Creighton's explanations of the facts 

 he records. In the chapter on small-pox, which is likely 

 to be the one first consulted, we find a passage which 

 disaiTns criticism : " It has been the fate of small-pox as 

 an epidemiological subject to be invested with bigotry and 

 intolerance." Yellow fever has as yet hardly sunk to that 

 deplorable level ; and as Dr. Creighton's theory appears 

 to be that " the dysenteric matters of the negroes " carried 

 on the slave ships " had themselves in turn bred an infec- 

 tion of yellow fever for the whites," it may be asked 

 whether the alleged protection of Africans of pure blood 

 from the infection of yellow fever " in all circumstances 

 ashore or afloat, . . . not by acclimatization but by some 

 strange privilege of their race," is either supported by all 

 recent authorities, or not capable of the explanation that 

 in infancy they may pass through some disease too slight 

 to be recognized as yellow fever, but which serves to 

 confer immunity. 



The general impression left upon the mind by this 

 history is that it would have been a wise policy to make 

 i two books instead of one out of the materials collected 

 — in one simply to bring together such facts as Dr. 

 Creighton's industry has gleaned from the authorities, 

 and in the other to enter upon the questions of etiology, 

 which are bound to give rise to interminable discussion. 



Besides those we have mentioned, gaol fevers, in- 

 fluenzas, " the French pox," and scurvy in early voyages, 

 are the principal diseases treated of in this volume. In 

 dealing with influenza Dr. Creighton draws attention to 

 the relation in point of time between the outbreaks in the 

 latter half of the sixteenth century and great epidemics 

 of plague, and a somewhat similar relation between fever 

 and influenza and exceptional climatic conditions in the 

 years 1657-59. 



OUR BOOK SHELF. 

 Mineralogy. By Frederick H. Hatch, Ph.D., F.G.S., 



of the Geological Survey of England and Wales. 



(London : Whittaker and Co., 1892.) 

 Dr. Hatch has followed up the publication of his 

 excellent " Introduction to the Study of Petrology," re- 

 cently noticed in these pages, by a little book on 

 mineralogy, which will, we think, be of equal service to 

 students. He has recognized the fact that for one person 

 who desires to enter upon a systematic study of 

 mineralogy, regarded as a natural-history science, there 

 are twenty who need only such an amount of mineralogi- 

 cal information as will enable them to profitably commence 

 the study of geology. We think, therefore, that the pro- 

 minent place given to the felspars, the pyroxenes, the 

 amphiboles, the micas, and similar common rock-forming 

 species in this work, is fully justified ; and not less so the 

 unsystematic but convenient grouping of other minerals 

 as "ores and veinstones," "salts and other useful 

 minerals," and " gems or precious stones." De Lap- 



