592 Trans icfions of the Society. 



the cell was picked off so as to display the diseased larvae. These 

 larvse were dead, of a yellowish colour, and almost liquid ; and on 

 examination afterwards their juices were found to contain numerous 

 moving bacilli. By means of a heated platinum wire, tubes of meat 

 infusion rendered solid by gelatin (10 per cent.), or by Japanese 

 isicgiass, were inoculated from several of these larvae and kept at 

 a suitable temperature. Development of bacilli, microscopically 

 similar to those seen in the juices of the larvse, occurred : the cha- 

 racteristics of this development will be presently described. Further, 

 in the tubes, kept at the body temperature, there was not only a 

 development of bacilli, but also of spores. 



These bacilli, as seen in the larval juices, measure about 1/7000 

 in. in length, and 1/20,500 in. in breadth. They are rounded or 

 slightly tapering at their ends, and often have a clear space near 

 one end. In the juices of the larva during life they apparently do 

 not produce spores, although after death spores abound. 



In the cultivation in the peptonized meat infusion, rendered 

 solid by agar-agar, the bacilli vary considerably in size, their average 

 length being 1/7260 in., some being as small as 1/10,000 in. and 

 others as large as 1/5000 in. When they have attained the latter 

 size, division of the rod seems to begin. They are always some- 

 what pointed at their ends. Their average breadth is 1/30,000 in., 

 varying from 1/35,000 to 1/25,000. 



The spores are largish oval bodies, averaging in length 1/12,000 

 in. (varying from 1/13,100 to 1/10,200 in.), and in breadth 

 1/23,700 in. (varying from 1/24,000 to 1/25,000 in.). 



In the agar-agar material the spores are generally arranged 

 side by side in long rows, and in old cultivations only a few bacilli 

 can be seen, some forming sjDores, some without any indication of 

 spores (figs. 10 and 11). That these small bacilli can produce such 

 large spores seems at the first glance at a microscopical specimen 

 almost inconceivable, but I have been able to trace on the one hand 

 the development of the spores in the rods, and on the other the 

 sprouting of the spores into adult baciUi. This can be done in 

 the following very simple manner : — 



Take a number of glass slides, each having a moderate-sized 

 cell hollowed out in its middle ; clean it, and pass through a 

 Bunsen flame several times to destroy any bacteria on its surface. 

 With a brush apply a very little vaseline around the depression, 

 and then place the slide under a glass shade to keep it from the 

 dust. Clean a number of cover-glasses, purify them in the flame, 

 and place them on a pure glass plate beneath another shade. With 

 a fine pure pipette put a small drop of sterihzed cultivating fluid 

 (meat infusion with peptone) on the centre of each of these cover- 

 glasses ; then with a fine platinum wire inoculate each of the drops 

 with the spores, or with non-spore-bearing bacilli; rapidly invert 



