436 PROCEEDINGS OF THE ACADEMY OF [1881. 



was found that under these circumstances a severe trachitis was 

 frequt'ntly i)roduced, and was attended by an abundant formation 

 of pseudo-membrane. Careful studies made of the false mem- 

 brane of diphtheria and of this false membrane showed that the 

 two were identical, both containing in abundance fibrin fibres, 

 corpuscular elements, and various foi-ms of micrococci. To deter- 

 mine wliether other inflammations of the trachea than that caused 

 by diplitheria or its membrane are accompanied by the formation 

 of false membrane, a number of experiments were made, and it 

 w^as demonstrated that the production of false membrane has 

 nothing specific in it, but that any trachitis of sufficient severity 

 is accompanied by this product. Careful studies also showed 

 that this false membrane does not differ in its constitution from 

 that of trne diphtheria, except it be that the micrococci are not so 

 abundant in it. They always found some micrococci, and in 

 some of these traumatic pseudo-membranes they were almost as 

 numerous as in the diphtheritic exudation. 



Last spring the}' resumed tlieir investigations. Having heard 

 that there was a very severe epidemic in Ludington, Michigan, 

 Dr. Form.ad was despatched to examine cases and collect material. 

 He found a small town situated npon the shore of Lake Michigan, 

 in the centre of the lumber region, with inhabitants mostly 

 engaged in the lumber trade and in managing very numerous 

 large saw-mills. The town was all built upon high ground 

 except the Third Ward. This occupied a low swamp which had 

 been filled in largely with sawdust. The soil was so moist that a 

 hole dug in it would fill at once with water, and but few houses 

 had any attempts at cellars. It was in this district that the 

 disease had prevailed. Almost all the children had had it, and 

 one-third of them were said to have died. Dr. FoTmad examined 

 a large number of cases, obtained a supply of diphtlieritic mem- 

 brane and brought home pieces of the internal organ of a child 

 upon whom he had made an autopsy. La ever}^ case the blood 

 was found more or less full of micrococci, some free, others in 

 zoogloa? masses, others in the white blood-corpuscles. The 

 organs brought home also all contained micrococci, which were' 

 especially abundant in the kidneys, where they formed numerous 

 thrombi, choking np and distending the blood vessels. In the 

 summer of 1880 they examined the blood of several cases of 

 endemic Philadelphia diphtheria, and in no case found au}^ new 

 elements in it. I3ut during the present summer the}- had found 

 micrococci in the blood of Philadelphia diphtheritic patients, 

 showing that the differences in the diseases are simph' in degree, 

 not in kind. 



Experiments were now made with the Ludington material upon 

 animals. Inoculations were practiced under the skin, deep in 

 the muscles, and in the trachea. In all cases the result was 

 similar. A grayish exudation ai)peared at the seat of inoculation, 

 along with much local inflammation, the animal sickened, and in 



