462 



NATURE 



[April i^, 1875 



may we not ask, why does a scientific man occupy time 

 and attention in experimenting on it ? The experiments 

 recorded in this Journal were made with " the exudate 

 from the lungs of animals which had been slaughtered on 

 account of pleuro-pneumonia." It was assumed that the 

 virus of the disease was present in this exudate. We 

 should like to know on what evidence this assumption is 

 based. We believe that the virus of the disease is given 

 out in the breath, and is not found in any of the secre- 

 tions ; .md that none remains, or can be generated in the 

 system, after death. We have deduced this conclusion 

 from our own experiments ; and, according to our inter- 

 pretation, the experiments upon which Prof. Brown's 

 paper is based support the same view. Every competent 

 authority now believes that the virus of contagious pleuro- 

 pneumonia is communicated by a living diseased to a 

 living healthy animal. If the virus could be communi- 

 cated in any other way into the respiratory passages, there 

 is every reason for thinking that the disease would be 

 produced. If the virus got even into the blood, there is no 

 known reason for thinking that it would not reach the lungs 

 and produce the disease. When the Professor states that 

 he failed to produce the disease with the exudate from 

 diseased lungs, there is some ground for doubting that 

 the exudate contained the virus, and that the title of his 

 paper — " Observations on inoculation with the I'ints of 

 contagious pleuro-pneumonia" — is questionable, to say 

 the least of it. 



We have next to notice Dr. Voelcker's paper entitled 

 " Field Experiments on Pasture Land." We begin by 

 remarking that it is more like the production of a tyro than 

 of a man of well-earned replitation. Some eight or nine 

 years ago Dr. Voelcker suggested to his former pupils and 

 others a series of experiments for testing the efficacy 0/ 

 different manures. In the paper to which we invite atten- 

 tion, the result of one series of these experiments is given. 

 Dr. Voelcker did not superintend any of these experiments. 

 They were made in different parts of the country, by men 

 who, we presume, possess more than average fitness for 

 describing their own experiments. It is most desirable 

 that experiments of this kind should be carried out on 

 different soils and in different circumstances ; and, so far, 

 the scheme set on foot by Dr. Voelcker deserves our 

 highest praise. It is to the execution of the scheme, and 

 to his own report in particular, that we object. The 

 experiments were made at four different places. We are 

 not furnished with the analysis of the soil at any of these 

 places. Among the manures experimented with were 

 mineral superphosphates, Peruvian guano, crude potash 

 salts, bone-dust, &c. It is notorious that superphosphate 

 varies greatly in composition. It is equally well known 

 that of late years Peruvian guano has varied greatly in 

 quality. No man knows this better than Dr. Voelcker, 

 and yet in the report under review he does not give 

 the analysis of a single manure used in these experi- 

 ments. Under these circumstances we submit that false 

 conclusions are liable to be deduced from the results. 

 This sort of work is not science, and we call upon the 

 governing body of the Royal Agricultural Society of 

 England to put an end to it. When we examine with 

 care the tables and the conclusions sought to be drawn 

 from them by Dr. Voelcker, we see additional grounds 

 for offering this suggestion. Every farmer of e.\perience 



5 No manure 



S Crude potash salts 

 10 No manure 



knows that the quality of the soil varies exceedingly, not 

 only on the same farm, but in different parts of the same 

 field. Experimental ground should, therefore, be treated 

 with the greatest care. In most cases it will be necessary 

 to prepare it in a variety of ways. The \vriter has a piece 

 of ground under experiment which he manipulated with 

 the utmost care. It was dug to a uniform depth, ine- 

 qualities of surface and of soil removed by levelling and 

 mixing, and repeated crops of grain raised without any 

 manure before any experiment was made. No such care 

 appears to have been considered necessary in under- 

 taking the experiments on which Dr. Voelcker reports. 

 The tables bear out our view fully, as we shall briefly 

 show. In each place ten plots v.'ere laid out for experi- 

 ment, and two of the ten (Nos. 5 and 10) were left 

 unmanured. In page 431 we are favoured with the 

 result of one set of these experiiaeil'-'jand we take from 

 it the following figures : — 



Plot. Manure. Yield of grass per acre. 



Tons. qrs. lbs. 

 421 

 336 



3 3 26 



Dr. Voelcker concludes from these figures that crude 

 potash salts diminished the produce. Now, in looking 

 at the figures we find a greater difference between the two 

 unmanured plots than between the one to which potash 

 was applied and either of the others. Assuming that this 

 difference arose from difference of soil, what guarantee 

 have we that the crude potash salts were not applied to 

 a soil inferior to either of the two unmanured plots ? 



We take another illustration of our argument from the 

 table, page 432 : — 



Plot. Manure. Weight of grass per acre. 



Tons. cwt. lbs. 



3 Fine bone-dust ... ..413 o 



4 Mineral superphosphates and 



crude potash salts ... ... 3 19 4 



5 No manure ... ... ... 2 17 2 



6 Common salt ... ... ... 3 iS 2 



8 Crude potash salts 5 4 o 



10 No manure ... ... ■■■ ^ o 4 



Here we have the difference between the two un- 

 manured plots greater than the difference between one 

 of them (No. 10) and any of the manures named. 



The weight of grass from common salt was more than 

 that from one of the unmanured plots, and less than that 

 from the other. On which are we to rely in coming to a 

 conclusion as to the action of common salt on the land 

 of the experimenter ? And, again, are we to conclude 

 that v/hile bone-dust increased the produce above either of 

 the unmanured plots, and while crude potash salts in- 

 creased it still higher, a mixture composed of superphos- 

 phate and crude potash salts produced less than an 

 unmanured plot ? 



COOKE'S "FUNGI" 



Fungi: their Nature, hifluence, and Uses. By M. C. 



Cooke, M.A., LL.D. Edited by the Rev. M. J. 



Berkeley, M.A., F.L.S. — The International Scientific 



Series, vol. xiv. (London : Henry S. King and Co., 



1875.) 



'"P'HE names both of Dr. Cooke and Mr. Berkeley 



J- appear on the title-page of this work, but in the 



editor's preface it is stated that the whole of the manu- 



