158 Prof. B. Moore. The Formation of Nitrites from 



Conclusions. 



The following conclusions may, I think, be justifiably drawn from these 

 observations. 



(1) More than one variety of (non-toxic) endsporing bacillus, resembling 

 B. tetani in morphological characters, can be recovered from wound exudates 

 in cases of the disease. 



(2) There are at least three different types of (toxic) B. tetani. 



(3) The " U.S.A. type " of the bacillus — that commonly used for the 

 preparation of antitoxin — is not frequently obtained from wound exudates in 

 cases of the disease occurring among men who have received prophylactic 

 inoculations of antitetanic serum. 



(4) Culture in a selective medium, followed by agglutination of the 

 washed growth in presence of the three type sera, gives valuable information. 

 It is, however, apparently not so delicate a test for the presence of B. tetani 

 as is animal inoculation after culture of the wound exudate. 



The Formation of Nitrites from Nitrates in Aqueous Solution 

 by the Action of Sunlight, and the Assimilation of the Nitrites 

 by Green Leaves in Sunlight. 



By Benjamin Moore, D.Sc, F.RS. 



(Eeceived October 12, 1917.) 



(From the Department of Applied Physiology and Hygiene of the Medical Eesearch 



Committee.) 



The number of chemical changes brought about by the activity of light is 

 multitudinous, and the study of these reactions has been very intensive in 

 recent years. In the majority of the photo-chemical reactions, the effect 

 produced is that of hastening an exothermic reaction, and in this resembles 

 the action of a catalyst. The substances formed have a less content of 

 -chemical energy than the motber substances, and are usually of a more simple 

 structural type. In such cases there is no clear proof of transformation, or 

 conversion, of light-energy into chemical energy, and the light acts more as 

 -a detonator to a chemical reaction in which chemical energy is set free. 



The most important case of an endothermic reaction set up by the action 



