STUDIES OF TISSUES DURING LIFE, 241 



tents subjected to microscopic examination. This latter 

 part of the work was unsatisfactory when conducted with 

 the usual combinations of lenses employed in bacterio- 

 logical work. Satisfactory examinations could only be 

 made by the use of very high magnifying powers, about 

 2000 diameters, and unusually brilliant illumination. 

 When conducted under these conditions the sacs inoc- 

 ulated with matters from the pulmonary exudates of 

 pleuro-pneumonia were found to contain numerous mo- 

 tile points or dots of such extremely small size that it 

 was often impossible to decide as to their exact form. 

 Control-sacs not inoculated, but kept in the peritoneal 

 cavity of the same animal, manifestly under similar con- 

 ditions, did not reveal the presence of the minute bodies. 

 In referring at length to this investigation it is not 

 my purpose to discuss the object of it, but only to 

 direct attention to this novel technique, which seems 

 capable of much wider application. There is a group 

 of common maladies, such as measles, scarlet fever, 

 smallpox, etc., of the etiology of which we know noth- 

 ing, and on which it has hitherto been impossible 

 to shed important light by the usual bacteriological 

 procedures. Nocard and Roux have apparently re- 

 vealed to us a world of micro-organisms whose existence 

 has hitherto been unsuspected, and it is not unreason- 

 able to suppose that it is among this group that we are 

 to seek for the causative agents of many specific dis- 

 eases whose etiology is as yet obscure. 1 



1 An excellent review of the paper of Nocard and Roux is to be 

 found in the Philadelphia Medical Journal of June 11, 1898. 

 16 



