Out of this number twenty-five were officials, viz. five lawyers, six medical men, six chemists and eight engineers. Four officials were further managers of artificial sewage purification works, but not one single manager of natural purification works, i.e. a sewage farm manager, was called, the term “sewage farm manager” being used here to indicate an official whose sole duty it is to manage a sewage farm. The entire absence of this latter class of official is so striking that it cannot be due to accident, but must be the outcome of a settled policy not to reopen questions conclusively settled by previous inquiries. Another point that strikes the observer is that the Commission only called one zoologist and one botanist, as it is to these scientists that belongs in the first instance the question of studying the fauna and flora of sewage before the subject is taken up by other branches of natural science. Speaking on the whole, the evidence taken by the Commissioners forms very interesting reading, and ought to be carefully studied by those who have to deal with the subject. When now and again opinions are expressed, which seem directly opposed to each other, it must be borne in mind that here, as in other things human, unanimity of opinion, though much desired, is apparently unobtainable. To understand the conclusions fully, at which the Commissioners in their Interim Report have arrived, it ought to be pointed out that they had either to accept the recommendations in favour of land passed by all previous Royal Commissions and authoritative inquiries, or they had to show by incontestable evidence that their predecessors had made grievous mistakes, and where! Of these two courses, the present Commissioners have adopted, no doubt for very good reasons of their own, the first, and they have started therefore, in the conclusions to which they have come, at the point where previous inquiries had left off, viz. that land treatment is a very proper method of sewage purification. But before referring more in particular to their observations on land treatment, it will be necessary to point out that the Commissioners evidently divide all methods of sewage purification into two main classes, viz. natural and artificial methods. Into the former they only place land treatment, whilst they call all other methods artificial. This division seems to have given a great deal of offence to all those who have expressed decided and frequently very one-sided views in favour of the “bacterial” treatment of sewage; but on closer examination it cannot be denied that the Commissioners were quite right in forming this view, as the following remarks will show.