216 MICROBES, FERMENTS, AND MOULDS. 
united in the form of zoogloea, that is agglutinated in 
small masses ; others, again, in the colourless corpuscles 
of the blood. All the organs, and especially the 
kidneys, were likewise filled with them. 
With the materials gathered at Ludington, Wood 
and Formad made some experiments in cultures, and 
were able to inoculate rabbits with croup. These 
inoculations were made subcutaneously, in the muscles 
and trachea, and were followed by the production of 
false membranes, and the animals died with all the 
symptoms of diphtheria. The blood was full of micro- 
cocci. An examination of living animals showed that 
the micrococcus first attacked the colourless corpuscles, 
within which their vibratile motion could be observed. 
The corpuscle changed in appearance, the granules dis- 
appeared, and it became so full of micrococci that they 
could no longer move: they grew until they caused the 
rupture of the corpuscle, and then escaped in the form 
of an irregular mass, which constitutes the zoogloea. 
Corpuseles filled with micrococci were found in the 
false membrane ; in the small vessels, which they dilate 
and completely obliterate; and even in the marrow of 
the bones. 
Cultures made in flasks afforded important results. 
A comparison of the sowings made with micrococci 
collected at Ludington with those found in the 
ordinary diphtheritic angina, which is common at Phila- 
delphia, showed a great difference in the vitality and 
virulent properties of microbes derived from these two 
