[October, 
5^4 Sanitary Agency of Light. 
wriggling movement which might be called mendacious. 
Endeavouring to show that if it was wrong on one 
point, it was right on another, it argues that the repor 
referred to was really unchecked, because Mr. Fitch s little 
memorandum was not written until after it was finished, 
thus ignoring the fadt mentioned in Dr. Cnchton-Browne s 
letter that Mr. Fitch accompanied him on some of his visits 
to schools, and had opportunities of checking his observations 
while they were being made.” 
IV. SANITARY AGENCY OF LIGHT: 
INFLUENCE OF THE SUN UPON THE VITALITY 
OF MICROCOCCI. 
t HAT light is essential to a vigorous state of health has 
long been admitted; but that the sun is a “sanitary” 
agent in the narrower sense of the term, a powerful 
ally in our war against so-called zymotic diseases, is not 
fully known : at least it has not yet met with practical 
recognition. 
M. E. Duclaux, some little time ago, laid before the 
French Academy of Sciences a series of observations on 
the influence of sunlight upon disease-bacilli. He has now 
extended his researches to micrococci. Of these minute 
beings he has specially examined six kinds, including those 
of Pemphigus, of Impetigo contagiosa, one found in the blood 
and urine of a patient suffering from rheumatic nodosities, 
&c. All these micrococci show a considerable resemblance 
both morphological and physiological, but they are neverthe- 
less specifically different. 
The adtion of the sun upon them differs accordingly as it 
is exerted upon an individual more or less mature, and 
whether it has been preserved in the dry state or in a culture- 
fluid. It varies, also, according to the season of the year. 
As regards this last fadtor M. Duclaux has not sought to 
eliminate the adtion of solar heat from the influence of light. 
This may, from one point of view, be regarded as a defedd 
