30 THE MICHOSCOPE. Feb., 



A few days ago I was greatly surprised to learn that the old 

 drinking cup was still in active use in our schools. This is 

 such a total disregard of all ordinary precautions for the preven- 

 tion of disease that it hardly seems possible. Yet in one of our 

 largest schools there are just six of these tin cups used by the 

 whole school for drinking purposes. Now it is a well estab- 

 lished fact that diphtheria is caused by a specific germ. It is 

 also well established that this germmiv reside in the throat 

 some time before the symptoms of diphtheria appear. Recent 

 investigations on this subject in New York City showed that a 

 small per cent of the children examined had this cause of diph- 

 theria existing in the throat, and yet did not exhibit any of the 

 symptoms of diphtheria at the time of the examination. Some 

 of the secretions from the mouths of such children, if carried to 

 the throats of others, would quite likely cause this disease. 

 When diphtheria is present in this city it would not be at all 

 surprising to find that in a large school there would be a small 

 per cent of children who could communicate this disease to 

 others. 



And vet, the school trustees allow a tin cup to be passed from 

 one mouth to another ! The use of a common drinking cup 

 by a number of school children should be rele,^ated to the ig- 

 norant methods of the dark ages. Not a cup should be pro- 

 vided by the school authorities. Each child should bring his 

 own cup. You cannot do anything better th m to forbid this 

 promiscuous use of the drinking cup. 



CORRESPONDENCE. 



How to find Diatomaceous Earth. — Mr. W. A. Terry of 

 Bristol, Conn., sends us the following : 



It is asked how we know when we have found Diatomaceous 

 Earth ? It is of course impossible to be absolutely certain until 

 the find has been examined under the microscope, still a collec- 

 tor of experience and good judgment will make few mistakes. 

 'J'he fresh water deposits are a' most invariably covered by a 

 layer of muck or peat. A light-colored stratum below muck 

 will be either lime, clay, or diatoms, U it is not sand Sometimes 

 all mixed. If the material dries of a light gray or ash color and 

 is also light in weight, it is almost certain to be rich in diatoms. 



