August 6 1903] 



NATURE 



^'7 



Rowland was an engineer, ^d this stood him in good ; 

 stead in all his researches, and nowhere more so than, 

 in the paper under' consideration. '' i 



In arranging his laboratory, Prof. Mendenhall tells! 

 us, many of his friends thought he was giving undue 

 prominence to the workshop, its machinery and tools, 

 and to the men to be employed in it, but he planned 

 wisely, for in original work "a well-manned and 

 equipped workshop is worth more than a storehouse 

 of apparatus already designed and used by others." 



So, too, it was in the optical work described in 

 part iv. ; the concave grating is the child of the 

 perfect screw, and he who would make a perfect screw 

 must follow Rowland as he described his method in 

 the article, " Screw," " Encyclopedia Britannica," 

 ninth edition. No. 33 of the Collected Papers. 



The secret is to correct the screw by grinding it 

 in a long adjustable nut longer than the screw itself; 

 thus, if the finished screw is to be 9 inches long, the 

 nut should be 11 inches; as the grinding progresses 

 the nut is closed in, and the grinding continues for 

 two weeks, the nut being turned end for end every 

 ten minutes and the screw kept in water constant in 

 temperature to within 1° C. all the time. 



It is not strange that machines which can rule 

 gratings are rare. 



The original paper on "Concave Gratings," No. 

 29, is a short one, but valuable details are given in 

 No. 49, "Gratings in Theory and Practice," and in 

 the " Encyclopgedia " article already referred to. 



The addresses which fill the last hundred pages of 

 the book are full of interest. To many who have 

 followed the accounts recently given in the pages of 

 Nature of the wealth and endowments of American 

 universities, " A Plea for Pure Science " will appeal 

 forcibly. Rowland was not satisfied that even America 

 was doing all that was needed. 



" The whole universe is before us to study. The 

 ifreatest labour of the greatest minds has only given 

 us a few pearls, and yet the limitless ocean, with 

 its hidden depths filled with diamonds and precious 

 stones, is before us. The problem of the universe is 

 yet unsolved, and the mystery involved in one single 

 atom yet eludes us. The field of research only opens 

 wider and wider as we advance, and our minds are 

 lost in wonder and astonishment at the grandeur and 

 beauty unfolded before us. Shall we help in this 

 grand work or shall we not? Shall our country do 

 its share or shall it still live in the almshouse of the 

 world? " 



Or, again, in his last address, " On the Highest 

 Aim of the Physicist," note his words, after speaking 

 of the work of the Physician : — 



" The aims of the physicist, however, are in part 

 purely intellectual; he strives to understand the uni- 

 verse on account of the intellectual pleasure derived 

 from the pursuit, but he is upheld in it by the know- 

 ledge that the study of nature's secrets is the or- 

 dained method by which the greatest good and happi- 

 ness shall finally come to the human race." 



Rowland unlocked some of the hidden chambers 

 himself; he did more than this, he put into our hands 

 the machine by which we may hope to forge the key 

 which will open the door leading to some of the 

 innermost recesses. R. X. G. 



NO. 1762, VOL. 68] 



k VINE DISEASE. - /• • .*. 

 Annates de Vlnstitut Central Atnpdlologique Royal 

 Hongrois. Tome ii. Pp. vii + 288 + plates. (Buda- 

 pest : Socidt^ d'Imprimerie ' et d'EditioiiS Pallas, 

 1902.) '!''', 



THIS admirably printed volume is devoted entirely 

 to an exhaustive study of the Rot livide of the 

 vine, a destructive disease due to the ravages of a 

 minute fungus known to botanists as Coniothyriutn 

 DiplodieUa. The memoir reflects credit on the author. 

 Dr. Istvanffi, not only on account of the thoroughness 

 and clearness of the 288 pp. of text, but also from the 

 beauty and completeness of the numerous (215) ex- 

 cellent figures set forth on the 24 plates. 



Of the fifteen chapters into which the work is 

 divided, the first deals with the somewhat extensive 

 history of this now almost ubiquitous malady, the 

 place of origin of which is not known with certainty, 

 but which appears to have been more probably south- 

 eastern Europe than the America to which we owe 

 so many pests. 



Chapters ii.-iv. are concerned with the description of 

 the rot as manifested on the shoots and leaves of 

 both native and American vines grown in Europe, and 

 the pathological alterations induced in the tissues by 

 the parasite. 



The principal signs when the disease is advanced 

 are brown spots and patches on the leaves, in the dead 

 tissues of which the minute black pycnidia appear; 

 the cortex shrivels, turns brown, and peels in fibrous 

 masses as it dries. The dead twigs also show that 

 the pith is destroyed, and similar pycnidia— frequently 

 accompanied by other fungi such as Botrytis, Pesta- 

 lozzia, CoUetotrichum, &c. — appear on the surface. 

 The dead twigs easily disarticulate at the nodes, and 

 the leaves above, even if not directly attacked, shrivel 

 and die because the diseased internodes cannot supply 

 them with water. A characteristic chambering of the 

 dying pith often precedes its total destruction, and may 

 remain visible at the nodes long after the pith of the 

 internodes has dried up. 



Microscopic examination shows that the hyphae of 

 the fungus causing these destructive effects permeate 

 all the softer tissues, and rapidly destroy the cortical 

 parenchyma with the formation of large gaps filled 

 with mycelium, and an interesting struggle for the 

 mastery between fungus and host is evinced as the 

 medullary rays, parenchyma and cambium attempt to 

 heal up the wounds already made ; in vain, however, 

 and the hyphae pass from cortex to pith vid these 

 medullary rays. 



It is, of course, impossible to enter here into the 

 numerous microscopic details, which, as might be 

 expected from so able a histologist as Dr. Istvdnffi, 

 are very thoroughly done, and embrace many dis- 

 coveries of interest, such as the sugar sphaerocrystals 

 in certain cells of the diseased cortex, the curious, 

 cambium-like callogene layer, &c. Every botanist will 

 find the careful microchemical reactions valuable, 

 and the coloured diagrams of the behaviour of the 

 diseased tissues are particularly instructive. . ; 



But it is not only the stems and leaves that are 

 invaded by this fungus; it also attacks the grapes 



