HO THE DISEASES OF DOMESTIC ANIMALS. 



into segments. Sometimes a number of rods ceased moving, and, 

 previous to lengthening out into filaments, arranged themselves into 

 patches of zooglea. 



" The division into two or more segments is not always a very- 

 rapid process. A rod, which was watched until it divided, was 

 made up of three segments, and one of them from the beginning 

 looked as if it might separate itself from the others ; but after six 

 hours of almost constant endeavor, it was still connected by a very 

 delicate thread, and before final separation, which took place after 

 seven hours' observation, it was divided into two segments in a com- 

 paratively short time, so that, when it did escape from the other ap- 

 parently inactive pieces, it moved about the field of the microscope 

 like two freely movable links of a chain. 



"After assuming this motile phase for some time, the rods 

 lengthened out into spore-bea,r'mg filaments. 



" The lengthening of the rods into filaments is an extremely rap- 

 id process, and is apparently affected by the temperature. In five 

 hours, at a temperature of 32° C, a rod may have increased so as to 

 be from eighty to one hundred times its original length, and in 

 twenty-four hours the filament may be full of spores. If the tem- 

 perature be kept at about 28° C, the spore may not appear until 

 the thirty-sixth or fortieth hour. When the spores have once ap- 

 peared, all the other changes go on at an ordinary temperature of 

 from 12° to 18° C, but not nearly so rapidly, even when the prepa- 

 ration is kept in the sun for a few hours daily, as when artificial 

 heat is employed. On the other hand, a high temperature, 37°- 

 40° C, at once checks all development. 



" The filaments, when first formed, are perfectly hyaline, but 

 soon the central protoplasmic contents can be distinguished from the 

 gelatinous-looking sheath. The protoplasma next divides into nu- 

 merous short pieces about the size of the original rod out of which 

 the filament was formed. These contract, leaving clear empty 

 spaces between them, and often again divide to form still shorter 

 masses of protoplasm. 



" At each side of this transverse line of division minute clear 

 specks appear — the first indication of spores. These gradually in- 

 crease in size and luster, and as they increase the protoplasma dis- 

 appears ; in fact, the spores seem to be developed from the proto- 

 plasm. Soon after the appearance of the spores the filaments seem 

 to be made up of numerous segments, each segment containing one 

 spore, the spores lying at the adjacent ends of the segments. The 

 spores now begin to escape. The filament gradually disappears, and 



