542 



SCIENTIFIC NEWS. 



[Nov. 23, 1888. 



time no attempt had been made to check its course or 

 to note the conditions under which it occurred ; but, at 

 the suggestion of Mr. Plowright, two rows in juxta- 

 position were submitted to experiment on August 10th. 



The rows were 30 yards in length, the variety 

 selected Schoolmaster, and the conditions as absolutely 

 identical as possible, except that the one row was left 

 moulded in the ordinary way, while the other was " high 

 moulded" — that is to say, banked up on one side to 

 form a ridge, while the haulm was slightly bent over to 

 the other side. In the ordinary system of moulding, a 

 furrow is left along the top of the ridge into which it is 

 surmised that the spores fall, washed off by rain from 

 the foliage. The high moulding, it is supposed, obviates 

 this by securing the fall of the spores on the ground 

 between the rows, and not on the rows themselves. As 

 the disease appeared to be equally severe on both rows, 

 and was, moreover, far advanced, but little expectation 

 was indulged in that the results would be of any value. 



Nevertheless, on September 29th, the potatoes in the 

 two rows were lifted and examined, as dug, by Mr. 

 Barron and Dr. Masters. It speedily became apparent 

 there was a considerable difference between the two 

 rows, and that the tubers from the high-moulded row 

 afforded a much cleaner and more even sample. With 

 a view to put this general impression to a nu- 

 merical test, fifty tubers from each row were taken 

 indiscriminately, twenty-five by one observer, the re- 

 mainder by the other, so as to equalise, as far as possible, 

 the "personal equation." 



These hundred potatoes were then examined with a 

 more careful scrutiny, each one being cut open to 

 ascertain whether or no it was diseased. The result 

 was as follows : — Out of fifty taken from the row 

 moulded in the ordinary way, thirteen were found 

 diseased, or 26 per cent. 



Out of fifty taken from the high-moulded row five 

 only were noted as diseased, or ten per cent. No doubt 

 a more careful examination by the microscope would 

 have indicated a larger proportion of disease in each 

 case, but it is not likely that it would have very materi- 

 ally altered the proportion either in one direction or the 

 other. In order, however, to obtain further information 

 upon this point, twenty-five tubers from each row were 

 put aside for future examination. 



Bristol Naturalists' Society. — At the meeting held on 

 November 6th, Dr. Dallinger delivered a lecture on 

 " Putrefactive Organisms." The Rev. T. Hinks, F.R.S., 

 President of the Society, occupied the chair. The lecturer, 

 who was most cordially received, said his chief embarrass- 

 ment was the abundance from which he had to select. 

 He should, however, not dwell on the method by which 

 he had pursued his inquiries, or the results of labours 

 undertaken with the vastly improved means of later 

 years compared with those with less perfect instruments, 

 but would detail to them one of the most remarkable 

 results that had been brought out by him in his investi- 

 gations. Passing to the main point of his subject, the 

 lecturer said the larger of the group of minute organisms 

 with which he should deal were so small that in a square 

 box, having the diameter of a human hair for each of its 

 sides, a hundred millions of these organisms could easily 

 exist. Some of them, however, were five, ten, and even 

 twenty times less than these. If a drop of animal or 

 vegetable matter under putrefaction were placed in a 

 small quantity of pure water, and was inspected with 



the microscope, organisms of beautiful forms were seen 

 moving about in ceaseless activity. Dealing with the or- 

 ganisms themselves, he explained that various species 

 followed each other as the process of putrefaction went 

 on, each preparing that pabulum on which its successor 

 lived, and spoke of the marvellously rapid rate of their 

 reproduction. Pictures were shown illustrative of the 

 characters of the organisms and the method by which 

 they did their work — some by rising up and darting 

 down on the putrefying mass and tearing it with hooks, 

 others by bringing their weight upon it and acting as 

 hammers. So this unceasing change and activity went 

 on until the putrefaction was exhausted, when the mass, 

 in the shape of carbonic acid and water, became part of 

 the protoplasm of living things once more. Occasionally 

 the deposit or debris of exhausted fermentation became 

 subject to further fermentive action, particularly in warm 

 climates, and the tiny organisms, by their continuous 

 rising and striking down and twisting, absorbed in them- 

 selves and dissipated the debris. In conclusion, the 

 lecturer urged the young members to studiously pursue 

 microscopic or kindred studies, from which they would 

 derive unspeakable pleasure and profit. 



The Leeds Naturalists' Club and Scientific 

 Association. — At a recent meeting held at the Yorkshire 

 College, the President (Professor L. C. Miall, F.L.S., 

 F.G.S.) presiding, the evening was devoted to "Practical 

 Microscopy," when, under the direction of the President, 

 the process of preparing and mounting animal sections in 

 celluloidine was fully elucidated, this forming a supple- 

 ment to an evening on the same subject some three 

 or four weeks ago. On this occasion the object under 

 treatment was the " Honey Bee," which presents several 

 difficulties over animals of softer bodies, as the chitinous 

 integument and the two large air sacs on either side of 

 the body offer a firm resistance against the celluloidine 

 penetrating the internal tissues ; but by disconnecting 

 the head, thorax, and abdomen and careful manipulation, 

 the fluid celluloidin can be got to permeate and render 

 the object sufficiently solidified to allow it being cut into 

 sections by the microtome. This was demonstrated with 

 the most encouraging result before the members, trans- 

 verse sections being made through the head, and sections 

 through the abdomen were mounted and examined. An 

 interesting description of some of the important features 

 of the slides was given. After the demonstration, the 

 President gave a comprehensive lecture on the entire 

 process, commencing with the mode of killing the object, 

 passing on to subsequent methods of treatment and the 

 reagents necessary. 



Royal Botanic Society. — At the meeting held on 

 Nov. 10th, Mr. J. P. Gassiot, Vice-President, in the chair, 

 among other exhibits upon the table were plants of 

 Abrus precatorins, the so-called " weather plant." The 

 Secretary, in explaining the action of the plant, said he 

 could not do better than quote his respected friend, the 

 late Michael Faraday, who, during a lecture on table- 

 turning, remarked that effects noticed were often 

 incorrectly attributed to a certain cause, and thus the 

 movement of the table was ascribed to some mesmeric 

 influence rather than to the unconscious mechanical 

 act of the operator ; and thus the action of the weather 

 plant was put down to atmospheric or other influences at 

 a distance of time or place rather than that of the imme- 

 \ uiate habitat in which the plant might be at the moment. 



