September 28, 1905] 



NA TURE 



537 



photomicrographs of etched metals and alloys, some 

 astronomical and spectrum photographs, and Mr. 

 Edgar Senior's photomicrographs of sections of photo- 

 graphic films, including those of colour photographs 

 by Lippmann's process which demonstrate that the 

 silver deposit is in layers. 



In the trade section there are many interesting 

 exhibits. Doubtless the greatest novelty is the demon- 

 stration of the three-colour process called " pinatype," 

 which is claimed to be the amateur's method of colour 

 printing on paper. Three prints in chromated gelatin 

 are made from the ordinary three transparencies, and 

 these are each caused to absorb its proper colour by 

 soaking it in the proper dye solution. The prepared 

 paper that is to bear the print is squeegeed on to 

 each of these coloured " print plates " in turn, and 

 duly absorbs the colour. Thus the three colours are 

 absorbed into a single film. The examples we saw 

 were of various degrees of merit. 



PROF. LEO ERRERA. 



LEO ERRER.A, professor of botany in the Uni- 

 versity of Brussels and member of the Royal 

 .\cademy of Belgium, whose death on .August i has 

 already been announced, was born in 1858. He 

 merited preeminently the title of professor, for not 

 only was he gifted as few men are gifted with the 

 faculty of giving a clear and precise explanation of 

 complicated problems, and of impressing upon the 

 minds of his hearers his conclusions, which were well 

 reasoned and supported bv facts and conceptions, but 

 he was also one of those teachers who recognised that 

 it is not possible to improvise a lecture, however 

 simple or commonplace, without bestowing upon it 

 lengthy and conscientious preparation. In addition 

 to the critical judgment which characterised his 

 teaching, he always kept it abreast of scientific know- 

 ledge ; each year, even in the case of his elementary 

 courses, his lectures were looked through, revised, 

 and brought up to date so as to include the latest 

 results in the subject. 



Prof. Errera was one of the first teachers in 

 Belgium who had the courage to declare that practical 

 work should take precedence of theoretical studies, 

 which alone had formed the ordinary courses up to 

 that time. He was convinced that a student should 

 only accept as true what he had verified for himself, 

 and that it is not sufficient to know scientific results 

 without becoming acquainted with the methods 

 employed. With this object he established in 1884, 

 when he was appointed professor in the university, 

 the laboratory for vegetable anatomy and physiology 

 which became later the Botanical Institute. 



He was wonderfully assisted bv the remarkable 

 facility with which he assimilated all current litera- 

 ture. He read Danish and Swedish without any 

 difficulty, and at the congresses in which he took 

 part, whether English, German or Dutch, he in- 

 variably excited admiration by his correct and ex- 

 pressive rendering of foreign languages. It was not 

 surprising that at the International Botanical Con- 

 gress held at Vienna last June he was nominated 

 president for the next congress, to be held at Brussels 

 in 1910. 



The worries of teaching did not cause Errera to 

 forget that it is the duty of every scientific man to 

 contribute to the increase of that knowledge which 

 has been handed down to him. His energy was 

 especially productive along four lines of research. 



When Darwin had attracted attention to the import- 

 ance of cross-fertilisation among plants and to the 

 part played by insects in the transfer of pollen, Errera 

 as earlv as 1S7S. recognising the full import of this 



NO. 1874, VOL. 72] 



discoverv immediately set to work to study with his 

 keen experimental insight the genera Penstemon and 

 Primula, and Geranium phaeiim. 



Later, while he was working in De Bary's labor- 

 atory at Strasbourg, he discovered in certain fungal 

 cells a substance then unknown which gave all the 

 reactions of glycogen. This is a body allied to 

 starch that was conclusively shown by the great 

 Claude Bernard to be of great importance in animal 

 physiology. By degrees Errera recognised glycogen 

 in all the'groups of fungi, and was able to assign to 

 it the same function, i.e. that of reserve carbohydrate, 

 as it has in animals. His first researches on this 

 subject were published in 1884, and constituted his 

 thesis for admission into the University of Brussels. 



Prof. Errera initiated a series of papers on the role 

 of alkaloids in plants. The origin and role of these 

 poisons in plant economy formed, and still forms, the 

 subject of discussion. The papers of Errera and his 

 pupils tend to prove that alkaloids are decomposition 

 products of nutrition, but that they may be_ utilised 

 by plants as a defence against herbivorous animals. 



He was one of those who realised the importance 

 which attaches to molecular forces in the structure 

 of living beings and in all the obscure phenomena 

 of nutrition. Basing his investigations primarily on 

 the important works of the physician Joseph Plateau, 

 the illustrious professor of the University of Ghent, 

 Errera showed that cellular membranes behave in the 

 same way as if thev obeyed the laws which regulate 

 the reaction of liquid films such as are produced in 

 blowing soap-bubbles. His first communication on 

 this subject dates from 18S6. 



But not content to lead the way in the domains 

 of science which we have outlined and to direct the 

 work of his students therein, he also pursued many 

 investigations in very diverse subjects. He did much 

 to improve the methods of microscopical technique ; 

 he simplified greatly the microchemical examination 

 of certain substances; he published ingenious theories 

 on the mechanism of sleep, and contributed lectures 

 on widelv different subjects varying from pedagogy 

 to natural philosophy; and all his publications were 

 marked by a clearness and purity of style that are not 

 surpassed' in the writings of any other man of science. 



Jean Massart. 



NOTES. 

 Mr. G. B. Buckton, F.R.S., author of several mono- 

 graphs on entomological and other subjects, died on 

 September 26, at eighty-eight years of age. 



We regret to see the report that Sir William Wharton, 

 who was prevented by illness from leaving Cape Town 

 with other members of the British .Association last week, 

 is suffering from enteric fever complicated by pneumonia. 

 His condition on Monday showed a slight improvement. 



.•\n earthquake shock was felt in Stirling, Dollar, and 

 .\lIoa shortly before midnight on Thursdr.y, September 21. 

 The shock travelled in a similar direction to that of 

 July 23, namely, to the south-east, but it was of slightly 

 longer duration and more violent in character. In Stirling 

 pictures and crockery were shaken and articles of furniture 

 moved, and a sound like thunder was heard. At Corton 

 railway signal-cabin all the bells were set ringing. At 

 Bridge of Allan the shock was felt very decidedly. In 

 Bannockburn and in the neighbouring villages the im- 

 pression was of a serious explosion. Comrle was only 

 slightly affected: a low tumbling sound was heard, but 

 no damage was done. 



