372 NATURAL SCIENCE. j UNE , 



letter was most clearly marked upon the plate. The bacteria had 

 grown thickly where they were protected from the light. Where the 

 light passed through the stencil-letter all growth was stopped. After 

 a longer incubation, under the same conditions, a few colonies appeared 

 over the illuminated area. For several reasons Professor Ward inferred 

 that these colonies had grown from spores that in some way were 

 protected from the light, possibly by being concealed behind other 

 spores, as the layer of jelly was not thin enough to contain a set of 

 spores only one deep. 



In another set of experiments, conducted both with solar light and 

 with electric light, the influence of the different rays of the spectrum 

 was examined. It was found that there was no bactericidal action, 

 at least in the case of Bacillus anthracis grown on agar-agar, in the red, 

 orange, yellow, and true green parts of the spectrum. The action 

 began near the line F and extended right on into the violet. All the 

 blue-violet rays were effective to some extent, but the maximum 

 action was about the line G. 



For a variety of reasons into which we cannot enter here, 

 Professor Ward concludes that the bactericidal action of these rays is 

 a direct action upon the living protoplasm of the bacteria. Many other 

 observers have shewn that light hinders the growth of other bacteria. 

 It has been shewn to have such an effect upon the typhoid bacillus and 

 upon several bacteria not associated with disease. Professor Ward 

 found that the growth of several fungi and moulds was hindered by it 

 and he is inclined to the view that the direct action of light hinders 

 the growth of all living protoplasm. 



We need not point out that Professor Ward's results, combined with 

 the results of previous investigators, have an important bearing upon 

 public health. It is unnecessary in these days to insist upon the 

 necessity of sunlight, or at least of daylight in all parts of dwelling 

 houses. But there is a minor although important issue raised. 

 Especially in large towns the washer-woman and the private laundry 

 are gradually being replaced by steam laundries, and we have grounds 

 for saying that in the majority of the larger institutions the drying of 

 linen is carried out by artificial heat in closed chambers. Care is 

 usually taken to secure proper ventilation of these, but no care is 

 taken to secure that light and especially direct sunlight has due access 

 to them. The clothes that used to dry on the village green or in the 

 private yard were thoroughly disinfected by the kindly rays of the 

 sun. Clothes dried in a heated chamber are returned to their owners 

 without having undergone this natural and harmless disinfecting 

 process. 



A New Worm. 

 We have received an interesting excerpt from the Proceedings of 

 the Academy of Natural Sciences of Philadelphia dealing with a new 

 genus of the Discodrilidae, which the author, Mr. J. P. Moore, terms 



