DEVELOPMENT OF THE BACTERIA. 109 



Two kinds of researches have been undertaken 

 for the purpose of discovering germs in normal 

 blood. The direct method, or microscopic exam- 

 ination, has given results very much disputed. 

 The blood contains, indeed, a considerable number 

 of little granules, of which the nature is doubtful, 

 and which it is difficult to distinguish from Micro- 

 coccus. Thus, while Liiders asserts that normal 

 blood contains germs, or spores, which only aw r ait 

 a favorable alteration in the fluid in order to de- 

 velop themselves, Rindfleisch formally denies their 

 existence. 



The indirect method, which consists in cultivat- 



in culture cells in which blood, in a moist state was kept under daily 

 observation for a week or more. 



" The method employed seemed the only one practicable for obtaining 

 blood from a large number of individuals without inflicting unwarrant- 

 able pain and disturbance upon the sick. It was as follows : One of the 

 patient's fingers was carefully washed with a wet towel (wet sometimes 

 with alcohol and at others with water), and a puncture was made just 

 back of the matrix of the nail with a small triangular-pointed trocar 

 from hypodermic syringe case. As quickly as possible a number of thin 

 glass covers were applied to the drop of blood which flowed. And these 

 were then inverted over shallow cells in clean glass slips, being attached 

 usually by a circle of white zinc cement. In dry preparations, which 

 are most suitable for photography, the small drop of blood was spread 

 upon the thin glass cover by means of the end of a glass slip. 



" The thin glass covers were taken from a bottle of alcohol, and 

 cleaned immediately before using; and usually the glass slips were 

 heated shortly before applying the covers, for the purpose of destroying 

 any atmospheric germs which might have lodged upon them. These 

 precautions were not, however, sufficient to prevent the inoculation of 

 certain specimens by germs floating in the atmosphere (Penicillium and 

 micrococci) ; and in nearly every specimen the presence of epithelial cells, 

 and occasionally a fibre of cotton or linen, gave evidence that under the 

 circumstances such contamination was unavoidable. It is therefore be- 

 lieved that any organism developing in the blood of yellow-fever, or 

 of other diseases collected by the method described, or by any similar 

 method, can have no great significance, unless it is found to develop as 

 a rule (not occasionally) in the blood of patients suffering from the dis- 



