160 RECENT RESEARCHES 



exposed to the air, we find the virulence either extinct or very feeble. 



Pasteur, Koch, and Greenfield, following out this line of disco- 

 very, found that similar attenuation could be made of the virus of 

 Anthrax, so that with equal certainty, animals which had suffered 

 from a mild attack produced by the attenuated virus, could be 

 inoculated with virus from the most severe forms without fear of 

 an attack. Modification has also been found to take place when 

 the virus has repeatedly passed through animals of another type ; 

 thus, Dr. Greenfield has proved that the poison of Anthrax can be 

 attenuated, and a protective virus be procured by repeated passage 

 of the bovine poison through the bodies of rodents. 



Not only medical, but also surgical science has been promoted 

 by the application of the Germ Theory. The idea suggested itself 

 to Lister that the reason why certain surgical injuries and opera- 

 tions were followed by pyemia, erysipelas, and the production of 

 putrefying pus, was that they became infected by bacterial germs 

 floating in the air, and that if we could exclude these germs, one of 

 the greatest scourges of surgery would be removed. In order to do 

 this, every precaution is taken during an operation to prevent the 

 admission of germs to the wounded surface, and to take care that, 

 if they do come in contact with it, they are immediately killed by 

 being exposed to a spray of diluted CarboHc Acid; the wound 

 afterwards being most carefully protected by antiseptic bandages. 

 The results produced by this mode of treatment, or at all events 

 by some modifications of it, have been most satisfactory. 



In summing up the conclusions we may arrive at, it will be 

 well to note that the actual value of new discoveries cannot be 

 appraised at once. Sometimes the discovery is undervalued, more 

 frequently it is over-estimated. Of no advance in Medical Science 

 is this more true than in the discoveries of Bacterial Pathology. 

 Though the remarkable fact of the relation of living organisms to 

 disease, which has been ascertained by the investigations of late 

 years, has been profoundly important, we must feel that at present 

 the study is in its infancy, and we should be careful not to be led 

 away by the interest of the observations, to jump at conclusions 

 which are not justified by the facts at our disposal, and to regard 

 the Bacteria as all and everything in the pathology of diseases. 



We may take it as proved, that many diseases are definitely 



