244 



NATURE 



[January 12, i8q; 



The gradual evolution of the perfect plant from the 

 seedling is indeed a subject of great interest to the phylo- 

 genist, although it is difficult— nay, impossible— to separate 

 those appearances which are merely hereditary from 

 those which are the result of varying outward conditions, 

 the more so because analogous conditions must have in- 

 fluenced the ancestors in past times even as they affect 

 their successors now. 



Amid such a mass of detail it is difficult to pick out 

 points worthy of special note. We select two only out of 

 many scores that might be mentioned. Some Onagrads 

 are remarkable for the intercalary growth which takes 

 place in the cotyledons, of which several illustrations 

 •»re given in Sir John Lubbock's book. They call to 

 mind the experiments of the late Prof. Dickie, who, by 

 suppressing the plumule of seedling castor-oil plants, 

 succeeded in inducing the cotyledons to continue their 

 growth and to assume dimensions much greater than that 

 which is habitual to them. 



The small tubercles on the root of Myrica californica 

 (vol. ii. p. 523, Fig. 663) have, so far as we know, 

 not previously been observed. The author compares 

 them to those found on Alnus cordifolia, and it would be 

 interesting to ascertain whether these outgrowths are 

 caused by an organism analogous to Schinzia alni, as 

 described by Woronin, or to that which induces the 

 peculiar tubercles on the roots of Leguminosas, recently 

 studied by Prof. Marshall Ward. 



Monocotyledons generally have been rather badly 

 treated by the author, although such genera as Potamo- 

 geton, Aponogeton, Orontium, and other Aroids, and 

 Palms (of which not a single illustration is given) would 

 have furnished examples at once interesting and easily 

 accessible. 



The work includes nearly seven hundred illustrations, 

 faithfully executed, and very valuable to the student. The 

 bibliography, in spite of its occupying no fewer than thirty- 

 eight pages, is the weak part of the book. Some of the most 

 important references are omitted, and whole series of species 

 whose mode of germination has been recorded and some- 

 times figured, have been passed over This only shows 

 how colossal has been the task which Sir John Lubbock 

 has set himself. We do not think the worse of the sun 

 for having a few spots on his disc, nor are botanists at all 

 likely to disparage this work because further research 

 might have added a few more illustrations. As it is, it 

 forms one of the most substantial and important con- 

 tributions to botanical literature that have ever emanated 

 from the press. It must continue to be a standard book 

 of reference for generations, and it will, we hope, stimulate 

 observers, according to their several opportunities, to 

 prepare similar monographs on the various organs of 

 plants. Maxwell T. Masters. 



EPIDEMIC INFLUENZA. 

 Epidemic Influenza : a Study in Comparative Statistics. 

 By F. A. Dixey, M.A., M.D. (London : Henry Frowde 

 and H. K. Lewis, 1892.) 



AFTER an epidemic disease has visited a country, 

 when the pathologist and practical physician have 

 had their say, there still remains the work of the statisti- 

 cian to be done. It is his province to sum up the results 

 NO. 12 1 1, VOL. 47] 



of the visitation in the clear light of hard figures, and to- 

 trace its onset and decline in mathematical curves. Such 

 work is of value in more than one direction. It preserves 

 for future generations a definite record of an epidemic of 

 greater precision than the impression left on the mind of 

 the physician : it enables a comparison to be drawn 

 between our own experience and that of other countries : 

 by the sifting and sorting of facts which it necessitates it 

 may lead to the discovery of relationships with alUed 

 diseases which may prove of no small value to the 

 pathologist. 



This work has been done for influenza by Dr. Dixey in 

 a very thorough and painstaking manner from the material 

 collected under the supervision of the Registrar-General. 

 It says much for the completeness of our registration 

 system in London, that it is possible to compile from 

 them such tables and curves as those with which we are 

 presented in this work, nor are such materials avail- 

 able from any other city in Europe. The only cities 

 whose statistics have been found by Dr. Dixey sufficiently 

 accurate for comparison with our own are Paris and 

 Berlin. 



Dealing first with the epidemic of 1889-90, he 

 shows in Table i the rise and progress of the disease 

 in London, as indicated by the weekly returns of fatal 

 cases, grouped according to the seven age periods adopted 

 in the official returns. Table 2 gives us, so far as the 

 returns of the period permit, the similar figures for the 

 epidemic of 1847-48. The similar characters of the two 

 epidemics are strikingly illustrated : in both we see the 

 same extreme suddenness of rise, and the same features 

 of decline, rapid at first, but becoming gradually slower 

 during the succeeding months. In the next two tables 

 are included similar figures for Paris and Berlin, and in 

 these, and in Table 5, the author gives an analysis of 

 the meteorological conditions accompanying the rise and 

 fall of the epidemic in the three cities. These are of 

 interest as showing how little influence the weather had 

 on the course of the disease as a whole. 



In the tables which follow — which are perhaps of 

 greater interest than any of the others Dr. Dixey has 

 compiled — the effects which influenza has exerted on 

 the mortality from other diseases in London and other 

 cities are shown. These eff^ects are of two kinds : in- 

 fluenza may aggravate the mortality of pre-existent dis- 

 ease such as phthisis or heart disease, or diseases such as 

 bronchitis or pneumonia may occur as complications of 

 influenza and swell its death-roll. It is interesting to 

 observe that whereas in 1847-48, which was in all respects 

 a more fatal epidemic than that through which we have 

 just passed, bronchitis showed the most extreme de- 

 parture from the normal mortality, pneumonia holds that 

 place in the late epidemic, while bronchitis falls into the 

 second rank. In this connection may be mentioned a 

 point of much interest illustrated in Tables 10, 11, and 12, 

 which deal with the age incidence of influenza and its 

 concomitant diseases. It is possible to draw curves 

 showing the special age incidence of each, and each 

 curve has its own special features. Now during an 

 influenza epidemic the pneumonia curve is found to be 

 modified so as to take on some of the characters of the 

 influenza curve, thus aff"ording corroborative evidence of 

 a conclusion already reached both in this country and in. 



