FRAGMENTS OF SCIENCE. 



283 



although this bacteriological action might be 

 connected with the corpuscles of the blood, 

 it was not confined to them, as the serum of 

 freshly coagulated blood was found to con- 

 tain some proteid substance which undoubt- 

 edly exerted a powerful bactericidal effect. 

 In July, 1889, Babes and Lepp recorded a 

 number of experiments in which they had 

 found that the blood of dogs which had been 

 vaccinated against rabies exerted a distinctly 

 protective action when injected into suscep- 

 tible animals, either previous to or along 

 with the virus procured from a rabid animal. 

 Ferran appears to have been the next ob- 

 server to accentuate this point. He was 

 followed by Bouchard in France, while 

 Behring and Kitasato in Germany, and then 

 Roux in Paris, and others in rapid succession 

 pointed out that there was in the serum of 

 the blood of animals vaccinated against 

 diphtheria and tetanus a distinct prophylac- 

 tic and curative agent which, however, it was 

 difficult to separate from the serum. In 

 1891 patients were treated in Berlin with a 

 serum prepared by Behring, and since then 

 this serum has been prepared and used in 

 nearly all civilized countries." 



Infected Drinking Water. There is a 

 growing tendency among physicians to be- 

 little the purely chemical examination of 

 potable water, and to rely solely upon the 

 results of the bacteriological tests. A recent 

 episode, the result of which seems at first 

 sight to strengthen this view, occurred during 

 the trials undertaken by the London Local 

 Government Board, in which water samples, 

 purposely inoculated with typhoid germs, 

 were sent for analysis to one of England's 

 leading chemists, and were by him pro- 

 nounced pure. The obviously weak point in 

 drawing such a conclusion from the above 

 occurrence lies in the fact that such a sample 

 of water would not be found in practice. 

 The mere fact that it contained no sewage, 

 to detect which is the chief purpose of the 

 chemical analysis, would almost certainly in 

 practioe preclude the typhoid bacillus, the 

 pure culture being only a laboratory product. 

 The same is practically true with all the 

 pathogenic micro-organisms which are liable 

 to occur in drinking water. The chemical 

 ingredients which the sewage supplies are 

 quite essential for the rapid growth and 



multiplication of the bacteria. In fact, a 

 favorable breeding ground is perhaps not 

 second in importance to the presence of the 

 germ itself, as the number of individual 

 microbes, up to a certain point, which gain 

 access to the human body, is probably of 

 much more importance than the kind of 

 germ. "The chemist," says Prof. W. P. 

 Mason, in an article in the Journal of the 

 American Chemical Society, "is unable to 

 say whether or not a sewage-laden water is 

 disease- bearing on any particular date, for 

 to him all sewage is alike, but he condemns 

 the water for the reason that, although it 

 may be harmless to-day, it is impossible to 

 predict what may be its condition to-mor- 

 row. Within the week I have been re- 

 quested to make a bacteriological exami- 

 nation of the water of a certain well, in 

 order to determine if it be affected by neigh- 

 boring cesspools. The physician who made 

 the request was impressed with the belief in 

 the paramount value of such an examination 

 and the comparative uselessness of chemical 

 analysis. I am quite convinced that, had I 

 followed his suggestions, I should have 

 sought in vain for any specific microbe, but 

 inasmuch as, upon chemical analysis, I found 

 that the chlorine ran twenty- four parts per 

 million, which is about ten times the local 

 1 normal,' and the ' nitric nitrogen I read 

 nine parts per million in place of 0116, I 

 condemned the water offhand without going 

 further. ... As Dr. Dupr6 has pointed out, 

 chemistry in such cases anticipates what 

 may happen in the future, and by timely 

 advice may prevent an outbreak of disease ; 

 while, on the other hand, the discovery of 

 disease germs in a water is only possible 

 after the water has become infected." 



A New Low-Temperature Apparatus. 



A most interesting and important demon- 

 stration of the efficiency of the process of self- 

 intensification of cold produced by expansion 

 alone without the aid of any extraneous arti- 

 ficial refrigeration is described in a recent 

 issue of Nature. The apparatus consisted 

 of three coils of narrow copper tubing ar- 

 ranged concentrically in a metal case, and 

 connected successively together. The gas, 

 say oxygen, enters the outer coil at a pres- 

 sure of one hundred and twenty atmospheres, 

 passing from this into the second, and from 



