

13 



periment and secured the same result bacteria were 

 developed, even with the greatest possible attention to 

 details of execution. He found, however, that if the 

 caustic potash were added to the urine, not in watery 

 solution but in the pure state after heating to redness, 

 no organisms were developed ; further, that if Bastian's 

 solution of caustic potash and urine were heated to 110 

 C., no development of life occurred. The error was 

 therefore the assumption that all organisms in the potash 

 solution, as well as in the urine, were destroyed by boil- 

 ing an assumption now known to be at variance with 

 the fact. Tyndall also narrates an instance which might 

 have been in less careful hands misinterpreted. He re- 

 moved from a clear, sterilized infusion a drop of liquid, 

 and to his astonishment found it, under the microscope, 

 swarming with bacteria ; examination of a second drop 

 showed none. The mystery was soon explained ; he 

 had cleansed his pipette before taking the first drop with 

 distilled water, a drop of which had remained in the tube, 

 and which contained, as examination of the water in the 

 bottle revealed, numerous bacteria. In these days pi- 

 pettes are cleansed, not with distilled water, but by a 

 Bunsen flame ; knives, needles, test-tubes, flasks, etc., 

 are considered sterilized after heating for five minutes to 

 150 C.; and fingers are allowed under no circumstances 

 to touch anything which could possibly come into subse- 

 quent contact with the culture. 



A consideration of the difficulties thus briefly sketched 

 in the way of even the accurate recognition of bacteria, 

 discloses the value to be attached to many publications 

 concerning these organisms which exhibit but too often 

 the author's neglect to comply with, sometimes even his 

 ignorance of, the elementary requirements of principles 

 and practice. As illustrations I shall select from the 

 mass of literature of this description a few which, from 

 the eminence of their respective writers in other depart- 

 ments of medicine, have attracted considerable attention 

 without as well as within our professional ranks. Some 

 four years ago a most genial and accomplished gentle- 



