June 8, 1900.] 



SCIENCE. 



909 



it is to reduce the organic matter by putrefac- 

 tion to soluble compounds. Further, in the 

 coisa'sely porous and intermittently aerated con- 

 tact beds, in which the soluble material from the 

 septic tank is allowed to staud, are afforded the 

 best conditions for the action of the aerobic 

 or nitrifying bacteria. Experience with this 

 method shows that even the solid material from 

 the raw sewage, which in the septic tank is 

 differentiated as a scum at the surface and a 

 deposit at the bottom, is also slowly acted upon 

 by the bacteria so that the quantity in the tank 

 is not appreciably changed after the colonies 

 have become firmly established. In the contact 

 beds also the aerobic bacteria establish their 

 colonies in a few weeks and appear in the form 

 of slime, which adheres to the surface of the 

 cinder or other porous material composing the 

 bed. Before passing from the septic tank to 

 the contact beds the effluent is aerated by allow- 

 ing it to flow in thin films over weirs. ' ' Perhaps 

 never in the history of engineering," said Mr. 

 Johnson, "has a new process, as revolutionary 

 as this one, established itself so quickly with the 

 highest authorities as has this new and simple 

 method of sewage disposal." 



In discussing the paper Mr. H. L. Eussell 

 likened the earlier attempts to accomplish the 

 bacteriological purification of sewage in a single 

 process to an attempt to raise the subtropical 

 rice and the temperate to subpolar barley in the 

 same field. Mr. F. E. Turneaure also discussed 

 the paper, emphasizing both the cheapness and 

 the efficiency of the new method. The paper 

 and the discussion aroused much local interest, 

 due partly to the fact that the city of Madison 

 against the advice and the urgent protest 

 of members of the Science Club, recently in- 

 stalled an expensive chemical plant for dis- 

 posal of its sewage, but has now been compelled 

 to abandon it as a complete failure and has 

 elected Mr. F. E. Turneaure to be City Engineer. 



Mr. Johnson's paper will probably be pub- 

 lished as a Bulletin of the University of Wis- 

 consin. 



Officers of the Club for the ensuing year were 

 elected as follows : Mr. E. A. Birge, President ; 

 Mr. C. S. Slichter, Vice-President ; Mr. E. R. 

 Maurer, Secretary and Treasurer. 



Wm. H. Hobbs. 



DISCUSSION AND CORRESPONDENCE. 



EEPLY TO PROFESSOR KINGSLBY'S CRITICISM. 



Only about a week ago my attention was 

 called to the criticism by Professor Kingsley of 

 my little book entitled ' Outline of Comparative 

 Physiology and Morphology ' in Science of 

 April 27th. I delayed answering because I was 

 at that time too much absorbed by many duties 

 connected with the close of the academic year 

 to allow my mind to be distracted by unpleasant 

 matters. I am now at comparative leisure and 

 undertake to show that many at least of his 

 criticisms are unjust. 



His points of criticism may be classified under 

 several heads: 



1. First and most numerous are general state- 

 ments which are true but not without ex- 

 ceptions. This was unavoidable in a bare out- 

 line such as the work professed to be. Our 

 distinctions in science are always sharper than 

 in nature. This is especially true in element- 

 ary science. If exact details and all excep- 

 tions were given we should certainly fail to give 

 a clear outline to be filled in by subsequent 

 study. Under this head come — («) the failure 

 to make exception of Fungi in giving the broad 

 distinction between animals and plants in the 

 nature of their food. If I had attempted abso- 

 lute exactness I should have been compelled 

 not only to make exception of greenless plants, 

 but to have discussed the economy of carnivor- 

 ous plants, and the question whether all plants, 

 even the greenest, do not supplement their 

 mineral food with more or less of organic food. 

 And then what would have become of my Oat- 

 line ? The very first necessity in an elementary 

 work is to renounce much, very much that we 

 should like to introduce, (b) Under the same 

 head comes the statement that animals by vir- 

 tue of the nature of their food must have a 

 stomach, without mentioning some exceptions 

 among parasites, as the tapeworm. (c) In 

 speaking of the general absence of the middle 

 ear in amphibians I did not make exception of 

 Anura. (d) In omitting mention of distinct 

 renal organs in Phyla lower than Mollusca. 

 Surely these objections are hypercritical al- 

 though in some cases especially (c) a foot-note 

 might be added giving exceptions. 



2. I said the last group may be regarded as 



