666 



SCIENCE 



[N. S. Vol. XXXI. No. 809 



tent that the average man knows not what to 

 believe, he sees so many contradictory state- 

 ments, drawings and photographs. 



It need hardly be pointed out that little 

 real progress can be made in any branch of 

 scientific work until the fundamental points 

 are placed on a much more secure foundation 

 than are many of the most important details 

 regarding Mars. 



It would seem that the best way of finally 

 settling some of these matters would be, as 

 suggested by Professor Aitken, to have them 

 passed upon by a committee of experts of 

 such well-recognized standing as to make 

 their unanimous verdict final and acceptable 

 to all scientific men. 



Then, and not until then, will these ques- 

 tions of the surface markings of Mars be 

 upon a dependable basis. 



It is also pertinent to point out the saving 

 of time which will result in many ways and 

 to many people by having a sure foundation 

 in this matter. 



The financing of such a project should not 

 be at all difficult considering the general in- 

 terest which attaches to Mars. 



0. D. Perrine 



■^ KIRCHER AND THE GERM THEORY OF DISEASE 



It would appear from Dr. Garrison's article 

 on " Fracastorius, Athanasius Kircher and 

 the Germ Theory of Disease,'" that I am in 

 the usual plight of one who attempts to fix 

 credit for the early suggestion of a scientific 

 theory. Apparently there is always to be 

 found some one who had thought it all out 

 long in advance of — the next man. But 

 though I have no desire to play the role of 

 special pleader for Athanasius Kircher, it is 

 only fair to point out that Dr. Garrison does 

 this early investigator an injustice when he 

 says that " Neither Kircher nor Leeuwenhoek 

 could have seen bacteria of any kind with the 

 lenses at their command. . . . His [Kircher's] 

 glass or microscope was only 32 power at 

 best." 



Aside from Kircher's apparently loose 

 statement that one of his microscopes showed 



* Science, April 1. 



objects " a thousand times larger," we have 

 no direct data regarding the magnifying 

 power of his lenses. We do know that the 

 simple microscopes of his and Leeuwenhoek's 

 time possessed great magnifying power and 

 that by their use many structures were 

 studied which at present we should not think 

 of examining without a compound micro- 

 scope. We know, too, that of the several 

 microscopes described or figured by Kircher, 

 one type was fully comparable to those of 

 Leeuwenhoek and, fortunately, concerning the 

 latter we have very full and definite informa- 

 tion. One of the Leeuwenhoek microscopes 

 still extant and described by Harting, had a 

 magnifying power of 67 diameters. The 

 twenty-six microscopes presented to the Eoyal 

 Society of London, by Leeuwenhoek, varied in 

 magnifying power from 40 to 160 diameters. 

 The maximum power of those known is pos- 

 sessed by one still preserved in the Museum 

 at Utrecht, which magnifies 270 diameters. 



In the face of these facts and Leeuwenhoek's 

 detailed description of, for instance, the or- 

 ganisms found in scrapings from the teeth, it 

 hardly needs the additional evidence of his 

 illustrations to prove that this worker really 

 saw bacteria. No one believes that Kircher 

 anticipated by some two hundred and fifty 

 years Yersin's and Kitasato's discovery of the' 

 bacillus in the blood of plague patients, but I 

 still believe that " There is no doubt that long 

 before Leeuwenhoek's discovery, Kircher had" 

 seen the larger species of bacteria " in putrid 

 broth, milk and the like. Imperfect and 

 faulty as his observations must have been, he 

 had definite observation as a basis for his 

 theory of the animate nature of contagion. 

 Certainly, his conception of the role of flies in. 

 the transmission of disease marked an ad- 

 vance over the theory of Mercurialis. 



William A. Eiley 



kahlenberg's chemistry 

 To the Editor of Science: Inasmuch as- 

 possibly a large majority of teachers of first- 

 year college students will agree with Dr. Hop- 

 kins in his criticism' of Lewis's review of 

 ' Science, N. S., XXXI., p. 539. 



