The coefficients which Ross introduces are the measures of variation due to mortalifrjr, natality, immigration and emigration of the non-aflfected and affected persons respectively. From a set of equations containing these coefficients, the total population and the ratio of the affected to all its members, he gets an equation giving the proportion of the total popu- lation affected at a given time.^^ The curve of which this equation is an expression is, in the simplest case, the regular bell-shaped curve, in other words, the assumption that the inf ectivity ratio is constant or pro- portional to the number of persons affected gives curves which are not irreconcilable with the hypothesis of decline from exhaustion of suscep- tible material^ opposed by Brownlee. These studies in "à priori pathometry," still to be completed, give Ronald Ross a distinguished place in the modern English school of iatromathematicians.
In 1906, there appeared a little volume of verses with the title page "In Exile, by R. R. Privately Printed," of which the author says, in his preface.
These verses were written in India between the years 1891 and 1899, as a means of relief after the daily labors of a long, scientific research.i8
In a sympathetic review of this book. Dr. Weir Mitchell, a fellow medical poet, has said:
In any climate and nnder the most indulgent conditions, what he did would have been remarkable. In India the lack of sympathy on the part of his military superiors, abrupt army orders, limited means and absence of help seemed ever ready at his happiest approach to success to mock him with delays. He must have felt as if, at times, some malign fate stood ready with obstacles over which no energy, no self-assurance of ultimate victory could prevail. I know of no medical story more interesting, no research which so surely found what it exacted, that heroism back of which lay energizing sense of duty. . . . Bonald Boss, when half blind or exhausted with work, turned to verse and sought in a dificult field for the relief that change of mental occupation affords, for the making of good verse is not an easy occupation, as several of the greatest poets have confessed. This little book is an interesting record of moods of mind, of hope, despair, sorrow and final triumph. It gives one a vivid concep- tion of the effects of exile, personal losses and the torment of tropical condi- tions on a man with an imagination of high order, somewhat lacking for use in verse that which only much technical training can supply. There are many verses in this book which exacting self-criticism might have altered or left out. There are some easily amended defects of rhythm — ^verses which are needlessly obscure; but these concern me little. There are many quatrains of virile power, descriptions of eloquent force or notable passages of insight and deep feeling.io
Of Ronald Ross's poems, space permits the citation of but one, the
17 Boss, Proc. Bay. 800. Lond,, 1916, Ser. A, XCII., 207; 211 et seq.
IS Ck>lonel Boss has recently presented to the Surgeon General 's Library his youthful dramas "Edgar" and "The Judgment of Tithonus" (Madras, 1S83), "The Deformed Transformed, '^ and the foUowing books of original verses, viz., "Philosophies" (1909), "Fables" (1907), "Lyra Modulata" (1911) and "The Setting Sun" (1912).
i» Mitchell, Jour. Am. Med. Ass., Chicago, 1907, XLIX., 852.
