272 



NA TURE 



[January 19, 1905 



coloured inks, marginal or thumb indexes, proportional 

 differences, inverse functions, &c. On opening 

 Blacliic's " handy " volume, the reader will be dis- 

 appointed to find that the compiler of the tables has 

 paid little attention to the points enumerated above. 

 A table of six-figure logarithms of four-figure numbers 

 occupies twenty-two pages ; the average difference for 

 each row of figures is given, but there is no room found 

 for proportional differences, so that the taking out of 

 the logarithm of a five- or six-figure number involves 

 an irritating calculation. Anti-logarithms are not 

 included, but there is a table of hyperbolic logs. 

 Sixteen pages are allotted to tables of natural and 

 logarithmic functions of angles, for increments of one- 

 sixth of a degree, without differences. Other tables 

 include reciprocals, squares and square roots, cubes and 

 cube roots, circumferences and areas of circles, heights 

 and areas of circular segments, and rhumbs in degrees. 

 There is an appendix giving some simple mensuration 

 rules, some old-fashioned practical geometry, and 

 definitions of the functions of angles, not as ratios, but 

 as lengths. 



The German tables are specially suitable for use in 

 the chemical laboratory. The main feature is an 

 eighteen-page table of five-figure logarithms of five- 

 figure numbers, arranged, with proportional differ- 

 ences for each row of figures, like the four-figure 

 logarithms contained in the first two pages. The 

 collection of physical constants at the end is such as 

 a chemist would be likely to require. There are no 

 anti-logarithms, nor is there a marginal index. The 

 size of page is ample, allowing of bold and effective 

 type. 



Second Report on Economic Zoology : British Museum 

 (Natural History). By Fred. V. Theobald, M.A. 

 Pp. X+197. (London: Printed by Order of the 

 Trustees of the British Museum, 1904.) Price 6s. 

 The recent development of British Museum activities 

 in the line of economic zoology, for which the insight 

 of the director is largely to be thanked, is re-expressed 

 in a second report, following quickly on the heels of 

 the first (see Nature, January 28, 1904, vol. Ixix. 

 p. 290). We congratulated Mr. Theobald on his first 

 report, and we repeat our congratulations, for the 

 volume does credit to his energy and ability, and to 

 the expertness of those inside and outside the national 

 museum who have given him assistance. Everyone 

 who has had even a little experience of the amourit of 

 work which is often required in order to answer 

 apparently simple questions from outside will 

 appreciate the skill which this report displays. The 

 volume contains a large part of the information 

 furnished by the director of the natural history depart- 

 ments of the British Museum to the Board of .Agri- 

 culture and Fisheries between November, 1902, and 

 November, 1903, besides replies to other correspondents 

 and some special notes of present-day interest. The 

 British Museum of Natural History' is not only one 

 of the greatest world-treasure-houses of scientific 

 material, it has also, in its staff, an almost unrivalled 

 wealth pf learning, and we cannot refrain from giving 

 expression to the widespread gratification that these 

 resources of material and knowledge are now being 

 utilised in behalf of the practical queries of the nation. 

 The volume deals with mosquitoes, sheep scab, weevils, 

 aphides, wire-worm, mites, leather-jackets, warbles, 

 ring-worm, liver-fluke, and a hundred other economic- 

 ally interesting pests— and always in a way that leads 

 us to respect Mr. Theobald's wide knowledge and 

 practical shrewdness. Wc hope that there will be 

 many such reports, for they are of a kind that enrich 

 the nation as well as science. That thev also con- 

 tribute to art may be illustrated by the report on the 

 grubs causing damage at Rye Golf Links. 



NO. 1838, VOL. 71] 



LETTERS TO THE EDITOR. 

 [The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither ean he undertake 

 to return, or to correspond with the writers of, vejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



The Heterogenetic Origin of Fungus-germs. 



.\n attempt has been made in Nature (December 

 22, 1904, p. 175), by Mr. George Massee, of Kew, to 

 question the validity of my conclusions because of certain 

 observations of his own of a totally different kind, which 

 have little or no bearing upon what I have brought 

 forward. 



What he says is this : — Dematium pullulans of de Bary 

 produces exceedingly minute colourless conidia which are 

 most widely distributed and are capable of passing through 

 " thick " filter paper. " Under normal conditions," he 

 adds, " these minute conidia on germination form delicate 

 hyaline hyphffi which give origin to a Cladosporium. If 

 cultures of these conidia become infested with bacteria 

 that form Zoogloea, the hyphae become invested with a 

 comparatively thick, brown cell-wall, and form either com- 

 pact masses of cells or irregular hyphae consisting of short 

 cells, constricted at the septa, exactly as shown in Dr. 

 Bastian's Fig. 12." He then refers to an illustrated paper 

 in the Kew Bulletin for December, 1898, in which he has 

 shown this process as it occurs in a certain disease of 

 Prunus japonica. He thinks his observations exactly 

 illustrate some of the facts which I have brought forward, 

 while L after carefully reading his paper and studying 

 his illustrations, think they are altogether beside the mark. 



He supposes the widely distributed conidia are not only 

 present in the hay infusion (which of course they may 

 be), but that they are able to pass through two layers 

 of very fine Swedish filter paper (not merely " thick " 

 paper, as he loosely puts it). Looking to his Fig. 5 and 

 the size of the conidia there shown, this, I think, is more 

 than doubtful. It is, however, altogether immaterial 

 whether such conidia are present in the original hay in- 

 fusion and are able to pass through the filter used by me 

 or not, because the next necessary step in his suggested 

 explanation is altogether wanting in my observations. 

 This step is that the conidia assumed to be present shall 

 produce delicate hyphEe, and that these hypbi-e, coming into 

 contact with masses of Zoogloea, shall " become invested 

 with a comparatively thick, brown cell-wall, and form 

 either compact masses of cells or irregular hyphae consist- 

 ing of short cells constricted at the septa." But I had 

 already privately assured Mr. Massee that all the pheno- 

 mena which I have described may be witnessed without 

 its being possible to meet with a single hypha of any 

 kind or a single one of the thick-walled, brown cells to 

 which he refers.' Yet for his explanation to have any 

 weight " delicate hyphae " should always be seen in rela- 

 tion with the Zoogloea masses, and as for the " thick- 

 walled cells " which are then formed being exactly like 

 what I have shown in my Fig. 12, I can assure Mr. 

 Massee he is absolutely mistaken. What I have repre- 

 sented in that figure are colourless products of segment- 

 ation of a Zoogloea mass (wholly unlike the colourless 

 conidia shown in his Fig. 5) which speedily assume a 

 brownish-black colour, and then, without any intervention 

 of delicate hyphae, at once grow out into mycelial filaments' 

 of the same colour. In accordance with his explanation, 

 the production of delicate colourless hyphae should be the 

 commonest thing possible, and should always be met with 

 at an early stage of the changes that I have been de- 

 scribing ; but, as a matter of fact, nothing is more re- 

 markable than the rarity with which any of the myriads 

 of Fungus-germs produced in a bacterial scum undergo 

 a further stage of development, with the production of 

 hvphae either colourless or coloured, and 1 can assure 

 >ir. Massee that he might work for three weeks or 

 more with such infusions as I have described without 

 finding a single specimen at all comparable with my 

 Fig. 12. It seems deplorable that in regard to such an 



1 This was in reply to a private letter to me ver>' similar to that which he 

 subsequently sent to Nati'RE. In this reply I asked him to come and 

 examine my specimens for himself, which he did not do. 



