MICROSCOPY. 377 



tion was considerably more marked than before, and he bases 

 on this his explanation of the detergent power of soap. It 

 seemed unaccountable that for cleansing purposes the com- 

 paratively neutral soap should be better than the alkaline 

 carbonate itself. The fact is, the detergent action of soap is 

 due to pedesis, by which minute particles are loosened and 

 diffused through the water, so as to be readily carried off. 

 Pure rain or distilled water has a high cleansing power, be- 

 cause it produces pedesis in a high degree. The hardness of 

 impure water arises from the vast decrease of pedesis, due to 

 the salts in solution; hence the inferior cleansing power of 

 such water. By the addition of alkaline salts and soap, we 

 have the alkali dissolving and the pedetic cleansing power. 

 At the same time we have a clear explanation why silicate 

 of soda is now largely used in making soap, this being one 

 of the few universal substances which increase the pedetic 

 and suspensive power of water. 



New Journals. 



Two new journals devoted to microscopical science and 

 kindred subjects have been commenced during the past 

 year Brebissonia, published in France, and the American 

 Quarterly Journal of Microscopy, published in New York. 

 The former is a spicy little journal, published monthly, and 

 devoted principally to Algology and Microscopical Botany. 

 The latter is more extensive in its aims, and promises to be 

 an honor to American journalism. 



National Microscopical Congress. 



A so-called National Microscopical Congress was held at 

 Indianapolis, August 14-17, 1878, to which most of the lead- 

 ing microscopists of the United States were invited, and in 

 which many of them participated. Some sixteen microscop- 

 ical societies were represented by delegates, and many cred- 

 itable papers were read. Of course, in this first meeting 

 there was much informality, and some resolutions were in- 

 troduced, and some adopted, which, no doubt, will be recon- 

 sidered at the next Congress, which is to be held at Buffalo, 

 N. Y., and will be much better attended. 



