266 THE AMERICAN MONTHLY [Sept., 



Koch's method for examination of the microbes to be 

 found in air. — The quantity and different forms of the bacteria 

 in any given situation or dwelling house or apartment can be 

 determined. Koch uses shal'ow glass capsules about 2 inch 

 deep and 2 inches in diameter, in which he places sterilised gela- 

 tine. These are placed inside tall glass cylinders, about 6 inches 

 high, the mouths of which are closed with large cotton wad- 

 ding plugs. The glass capsule is lowered into the cylinder, and 

 again removed from it by means of a piece of soft metal bent at 

 right angles. After the whole has been sterilised, the cotton 

 wadding plug is removed, the gelatine is left exposed for about 

 10 minutes, the plug is reinserted, and organisms that have set- 

 tled on it are allowed to develop at the temperature of the room. 

 These soon make their appearance as small white, yellow or 

 pink points according to the nature of the germs that are pre- 

 sent in the air. In addition to these, however, a number of 

 flufty white, green, or black forms make their aj)i)earance. The 

 former consist of bacteria, sarcina or yeasts, the latter of peni- 

 cillia, mucors, and aspergilli. 



A simpler method is merely to allow the germs to settle on 

 plates of sterilised gelatine or potatoes, which are left uncovered 

 for a time. This will give a notion of the species to be found 

 in any given place, but not the number. 



MEDICAL MICROSCOPY. 



A Tuberculosis Congress has been held at Paris, and the 

 members have arrived at the conclusion that all persons dying 

 of "consumption" should be cremated, as the earthworms bring 

 the germs of tuberculosis to the surface, and so distribute the dis- 

 ease. The congress proposed this order of the day, after hear- 

 ing an account of experiments made at the Botanical Garden of 

 Lyon, by Messrs. Lortet and Despeignes. These two well-known 

 doctors have filled with earth some flower-pots. In each pot 

 they have put earthworms with spittle of tuberculous patients 

 and fragments of lungs taken from their dead bodies. A month 

 after, they have ascertained that the earthworms contained a 

 great number of tuberculous bacilli and that the Guinea pigs 

 inoculated with these died soon with general tuberculosis. — 

 Rene Samson, Paris, France. 



