250 



NATURE 



[January ii, 1894 



at a loss to discover. Nor was even the inventor appar- 

 ently satisfied, for we are told in the report that '' in order 

 to still further improve the quality of the effluent by 

 longitudinal filtration, by oxidation, and by the action of 

 micro-organisms, Mr. Scott Moncrieff devised what he 

 has termed nitrifying channels. These in their sim- 

 plest form consist of half-channel pipes joined together 

 with cement and filled with coke." These channels were 

 originally 30 feet in length, but subsequently they were 

 increased to 80 feet. As regards the efficiency, or rather 

 inefficiency of these channels, we are able to form an 

 opinion from analyses given on pp. 19 and 20 of the 

 report ; from these it appears that the free ammonia 

 befor'!-vz.s 3'2 parts per 100,000, and <2//<?r passing through 

 the 80 feet channel 3 '6 parts, whilst the albuminoid am- 

 monia was '8 part before, and "64 part after, respectively, 

 whilst in no case was more than a very small proportion 

 of nitrate discovered in this effluent, showing that these 

 channels are " nitrifying "in name only. 



If we now inquire into the machinery involved in 

 producing these results, we find that for a household of 

 ten to twelve persons, the filter-bed was 10 feet long by 

 24 feet wide, or 25 square feet in area, whilst the so called 

 nitrifying channel superadded to this was 80 feet in length 

 {the diameter of these channels is not given). For a 

 population of 1000 persons, therefore, a filter-bed, 

 upwards of 2000 feet square, and a nitrifying channel, 

 between 6000 and 7000 feet in length, would be necessary. 



It is difficult to discover what claim to novelty Mr. 

 Moncrieff's system possesses ; the upward filtration of 

 sewage was practised years ago, and has been generally 

 abandoned on account of the far superior results obtained 

 by downward intermittent filtration. As regards the 

 nitrifying channels, these are simply downward filters of 

 a very clumsy and expensive form, the inefficiency of 

 which is attested by the analyses published in the report. 

 One novelty indeed there is in Mr. Moncrieff's filters, to 

 which they doubtless owe their "up-to-date "title of" cul- 

 tivation filter-beds," for we are informed that when a 

 new filter-bed is started it is " inoculated" with the liquid 

 contents of an old one I As already pointed out, in the 

 absence of any analyses of the raw sewage, the report 

 gives us no information as to the work really done by 

 the " cultivation filter-bed," but the effluent coming from 

 it certainly contrasts very unfavourably with good 

 effluents obtained either by filtration, irrigation, or chem- 

 ical precipitation ; as regards the work done by the 

 " nitrifying channels," the analyses demonstrate this to 

 be simply deplorable. 



In conclusion, we would remark that the chemical 

 analyses might advantageously have been made more 

 complete, so as to render the figures comparable with 

 those given in the best investigations on the purification 

 of sewage ; and we would point out that an analysis is 

 not rendered more exhaustive either by expressing each 

 determination in parts per 100,000 as well as in grains 

 per gallon, or by drawing out the results in elaborate 

 but meaningless curves of divers colours. 



ARTHUR MILNES MARSHALL. 



A GLOOM has been cast over the opening year by 

 ■^"^ the news of what can only be described as a national 

 calamity. Like his friend. Prof F. M. Balfour, Milnes 

 Marshall has been cut off in the midst of a life of scientific 

 usefulness by an accident among the mountains which he 

 loved. On the last day of 1893 Prof Marshall, with 

 several companions, started from the hotel at Wasdale 

 Head for a day's climbing among the precipices of Scaw- 

 fell. All the dangers and difficulties had been passed, 

 and the party were looking for suitable views to photo- 

 graph. Dr. Marshall had mounted a few feet higher 

 than the others, and called out, " Here is the best place 



NO. 1263, VOL 49I 



for the camera," when almost immediately a large stone 

 was seen to fall, followed by his apparently lifeless body. 

 The precise details of the mishap will never be known — 

 whether he stepped or sat down upon a rock loosened 

 by the frost, or whether, as is thought by some well 

 qualified to judge to be more likely, a stone fell upon him 

 from above — must remain a matter for conjecture. The 

 melancholy fact is sufficient that a young and brilliant 

 student of nature passed in an instant from the full enjoy- 

 ment of health and strength to the " cold obstruction " of 

 death. 



Arthur Milnes Marshall was born in 1852, and in- 

 herited a love of natural science from his father, a gentle- 

 man well known in engineering circles, as well as an 

 enthusiastic naturalist and a microscopist of no mean 

 reputation. He was educated first at a private school, 

 and in 1871 entered St. John's College, Cambridge, where 

 he was one of the earliest students of that school of 

 biology of which he afterwards became so distinguished 

 an ornament. In 1876 he obtained the entrance scholar- 

 ship in natural science at St. Bartholomew's Hospital, and 

 entered upon the study of medicine. It is hardly too 

 much to say that this step was taken as a pis aller. He 

 looked forward with anything but satisfaction to the life 

 of a medical practitioner, and when, in 1879, he was 

 elected to the newly-created chair of zoology in the Owens 

 College, he entered with delight upon a career devoted to 

 the advancement of his favourite science. 



As might have been expected from the friend and com- 

 panion of Balfour his first work was embryological, and 

 consisted of a series of papers on the Cranial Nerves, 

 published in the Jotcrnal of Anato7ny and Physiology 

 and the Quarterly Journal of Microscopical Science 

 between the years 1877 and 1881. Though in matters 

 of detail these papers may need correction, and though 

 the " Segmental Value of the Cranial Nerves" is as much 

 open to discussion as it was when Marshall wrote his 

 thesis, these memoirs were at the time solid contributions 

 to our knowledge, and have furnished a basis upon which 

 other men have wrought. The culmination of his work 

 in this direction has been the great work on " Vertebrate 

 Embryology," of which an appreciative notice appeared 

 in these columns so recently that it is not needful to do 

 more than allude to it. 



In 1 88 1 the dredging operations of the Birmingham 

 Natural History Society gave him the opportunity of 

 studying the Pennatulida, and in the following year a 

 report upon these animals was issued under the joint 

 authorship of himself and his father. In this and in his 

 subsequent papers on the "Pennatulida oiihQ Porcupine 

 and Triton Expeditions," and of the " Mergui Archi- 

 pelago," written partly alone and partly in conjunction 

 with Dr. G. H. Fowler, he carefully elaborated the dis- 

 tinctions between the various forms of zooids and traced 

 the relationships of the genera on morphological grounds. 

 Strong reasons were adduced for dissentmg from the 

 classification propounded by Kolliker, though Marshall 

 never considered that he had enough material at com- 

 mand to justify him in proposing an alternative arrange- 

 ment. On the whole it is probable that these memoirs 

 will form his most lasting contribution to zoological 

 science. 



A paper on " The Nervous System of Antedon," con- 

 taining the results of an Easter vacation spent at Naples, 

 was valuable as establishing beyond question the views 

 of the Carpenters regarding the nervous function of the 

 central capsule and axial cords of Crinoids, but it is still 

 more interesting as an example of Marshall's clear and 

 logical method. 



Marshall was a born teacher ; his mind was of that 

 rare order which not only sees a problem clearly itself, 

 but is cognisant of every step taken in understanding it, 

 and hence is able to enter into the position of those who 

 approach it for the first time, and to see where their diffi- 



