February 20, 19 19] 



NATURE 



495 



the analytical work which has beer carried out to 

 mine thi chemical composition ol marine algse 

 brings out cli ncomplete and scrappj is oui 



knowledge ol thi chemical composition ol these 

 plants, and how untrustworthy and unscientifii is 

 much of the work which lias alread) been^done. 



Pmi S '• ii.it has bean done in 



France, Britain, and the United States dujung recent 

 times, and especially during the past thirS»years,jKn 

 the analysis ds, and he is specjlly sevjre 



ime "I his own countrymen for theia ignorance 

 of botanical nomenclature and for the cuijjrmpi with 



which they 1 1 ..it 11,11111. IS s|io\«> h\ ih.-ii 



failure to learn the rudiments ol the lik^uage- of 

 botany before undertaking to deal with \ bo 

 subject. Much of this criticism is just, an, I some of 

 the exampli the use of out-of-di and 



inexact nomenclature are sufficiently serioSfe to 

 that it was While thus dealinfc faithfully 



with his own countrymen, Prof. Sauvageawrecogi 

 that some chemis n the troublerto identify 



with sufficient care the species which* ihej Have 

 analysed. Thus he says that "the accuracy with 

 which Stanford names the plants studied inspires 

 more confidence in the reader than the uncouth ap- 

 pellations of Allan." 11 gnises that Ameri- 

 can workers like Wheelei and Hartwell have taken 

 care to obtain competent assistance in identifying the 

 species they have examined. 



At the same time Prdf. Sauvageau appears to under- 

 estimate the difficulty in which the careful chi 

 who wishes to identify and name his species con 

 sometimes finds himself. He himself offers a good 

 illustration of this difficulty in his reference to the 

 present wri work on the composition of 



five of our comma ds collected on the coast 



of Scotland. Two of these belonged to the genus 

 Laminaria, milar both in their appearance 



and structure and in their habitat. ["here is no diffi- 

 culty to one who takes the trouble to make himself 

 familiar with them either in distinguishing these 

 species, or in recognising from Prof. Sauvageau 's 

 own description thai what is called in my papers 

 /.. digitate is what he calls /.. clous tonii, and 

 that what I analysed undei the name /.. stenophylla 

 he calls / flexicaulis. Bui standard works of 

 reference which were consulted were not agreed as 

 to these names, which I used only after reference to 

 a distinguished botanical colleague; and to make as 

 certain as possible that there should be no mistake 

 as to what species were intended, a standard work 

 on seaweeds in . with which these names 



were used was referred to in one of my papers, 

 ss, Prof. Sauvageau writes: His L. 

 stenophylla is probably a mixture of that which Eng- 

 lish botanists call /.. digitata (/.. flexicaulis) and /.. 

 stenophylla. that being a close ally, if not a variety, 

 of L. flexicaulis." He himself does not appear to bi 

 clear either as to thi norm nclature of English botanists 

 iecies which were identified with so 

 much care. He can scarcely expect the chemist to 

 do more than accept the best botanical guidance to 

 be obtained on a point of this kind where, he admits, 

 the practice of botanists is not uniform. 



Another criticism which Prof. Sauvageau offers ol 

 the work of chemists is also valuable, and requires 

 careful attention from the chemist, but again one 

 cannot help thinking he would have been more effec- 

 tive if he had not att( mpted to press his criticism too 

 far. lie points out that if the analyses an to have 

 a scientific, and not merely an industrial, value, not 

 only should species be properly identified, but also 

 samples collected for analysis should be clean and 

 biologically pure, and obtained, if possible, from 



NO. 2573, VOL. I02] 



tin actual habitat, with a careful record of the 

 sea on, the condition ol growth, and the state 

 of the plants, whether fertile 01 sterile. \ll 

 this,, are important points which have too often 

 been neglected. The large common seaweeds are 

 frequently garnished with a greal variety ol othei 

 organisms, both animal and vegetable, making it 

 1 to procure even a reasonably pure sample. 



In some eases thes tnisms 1 an be removed, 



but it is generally difficult to remove them entirely. 

 It als,, introduces errors, as greal in main- case, as 

 those which are being avoided, if attempts are made 

 to wash the samples, as compounds which properly 



belong to them are als loved in the wasn-water. 



All that one can do is to colled reasonably pure 

 samples and to pick off all the foreign organ 

 which can be distinguished. In main cases, however, 

 the chemist was not attempting to analyse a pure 

 botanical species, but to determine the composition of 

 the impure substance used for some industrial purpose, 

 such as the drift-weed which is washed up on the 

 ' beach, and used as manure or for kelp-burning. The 

 value of such analyses is limited by the object in view. 

 Prof. Sauvageau has performed an important service 

 in directing the attention of chemists to the pre- 

 cautions which they require to take when they enter 

 on the systematic study of the composition of sea- 

 weeds or of any other spei ti - of plant. Our know- 

 ledge of the composition of seaweeds is still quite 

 rudimentary, and very valuable work might be done 

 in this field, by chemists with a competent knowledge 

 of the botany of seaweeds, or working in collaboration 

 with botanists who would collect and identify the 

 samples for analysis. The recorded analyses show 

 wide variations in the composition of seaweeds of the 

 same species, and Prof. Sauvageau is inclined, on 

 account of this, to cast doubt on the samples or on 

 the conditions under which they were collected. In 

 the present state of our knowledge this is scarcely 

 justified. Numerous well-authenticated cases of simi- 

 lar wide variations in composition are found in the 

 case of other plants, even when they appear to be 

 grown under similar conditions in the same locality 

 and are collected at the same stage of growth. 



James Hendrick. 



ITALIAN CLIMATOLOGY . 

 *"P WO more contributions by Prof. F. Eredia to 

 A our knowledge of the climate of Italy have 

 recently appeared, oni dealing with the normal mean 

 values of annual rainfall in Italy, and the other with 

 diurnal temperature variation in Sicily In the. first 

 paper, " l.e Medie mnm.di dell.i quantita' di Pioggia 

 in Italia" (Giornale del Genio Civile, anno lvi., 1918), 

 the mean values for each calendai month are shown 

 for nine- well-distributed cities on the basis of the 

 fifty-year period 1866 1915; and it is calculated that 

 lb. values are correel to within 5 mm. for the rainier 

 winter months and 9 mm. to 12 mm. for the summer 

 months of smaller rainfall and more irregular dis- 

 tribution. In northern or continental Italy, 

 exemplified by Milan and Turin, the seasonal variation 

 of rainfall is not prominent, but the wettest , 

 are- early summer and autumn, the highest figures 

 for May and October. In peninsular Itah the 

 typical Mediterranean feature of wet winters and dry 

 summers is conspicuous, especially in the extreme 

 south. Thus at Palermo the figure for December, the 

 wettest month, is 108 mm. (4-3 in.), and for July, the 

 driest, only 7 mm. (0-28 in.). The wettest city quoted 

 is Genoa, on the Ligurian coast, where the wettest 

 month, October, has 190 mm. (7-6 in.), and the driest, 



