30 MEETING OF INSPECTORS OF APIABIE8. 



w liich seem to me only explicable <>n tbe supposition that they also grow by 

 sending out buds from one end. A bacillus may be seen with a small. some- 

 what conical stained point attached to one end. though separated by a marked 

 division. This is certainly not the common mode of growth by fission, for there 



the rod -uvins to divide into two pretty equal halves, while here we have hut a 

 minute piece attached to one end. 



The mode of formation of spores may be traced in a similar manner to that 

 described above in the case of the sprouting of the spores. It is. however, as .-i 



rule, accessary to leave the organisms to grow tor ;i much longer time than in 

 the former instance. 1 have not found development of spores .-is :; rule before 

 twenty-three hours, bul this depends very much, apparently, on the amount of 

 fluid that was present and the number of bacilli introduced at the time of 

 inoculation. The first thing noticeable is that the rod begins to swell and 

 becomes spindle shaped. The swelling, which generally affects the middle of 

 the rod. may in some cases he most marked toward one end. increases in size. 

 and the center of the swelling gradually ceases to take on the stain. The cap- 

 sule of the spore is apparently also formed within the rod. and is not merely 

 i he outer part of the rod. In three or four hours the rod is seen to have almost or 

 completely disappeared, leaving the spore lying \'wr or within t he faint outline of 

 the original bacillus. It seems to me that the view that spore formation occurs 

 when the food is getting exhausted is correct, for the time at which this appear- 

 ance is found depends greatly on the drop placed on the cover glasses, and I 

 have found in one experiment that in one specimen, after twenty-three hours, 

 most of the rods were forming spores, while in another specimen where the drop 

 was much larger there was no trace of spore formation after twenty-eighl 

 hours. I have here described the results of my earlier and rougher attempts 

 to study the formation of spores. I have, however, now improved the method 

 in the following way. As I have just now shown, the period at which spores 

 are first seen seems to depend mainly on the amount of fluid used and the 

 number of bacilli introduced, and as in the above method, both these factors 

 vary in each case, one can not get a regular series of preparations showing the 

 different stages at different times. In studying the sprouting of spores the 

 amount of fluid and the number of spores does not matter, tor if sufficient nutri- 

 ment is present and a proper temperature is maintained the spores musl sprout, 

 and probably they always take about the same length of time. The difficulty of 

 obtaining a series of specimens illustrating spore formation is easily obviated 

 in the following manner. Take a pure flask containing a small quantity of 

 sterilized infusion and inoculate it from a cultivation containing only bacilli. 

 Place it in the incubator for two or three hours so that the bacilli may increase 

 somewhat in number and diffuse themselves through the liquid. Tims the culti- 

 vating material contains bacilli pretty equally diffused through it. and if after 

 shaking the flask drops of equal size are taken, each will probably contain 

 about the same number of bacilli. The minutest quantity of fluid can easily be 

 obtained by means of a syringe having a fine screw on its piston and a large 

 nut revolving on this screw. The circumference of the nut being equally divided 

 into a number of small segments, the same quantity of fluid can always he 

 expelled from the syringe. By proceeding in this way equal-sized drops con- 

 taining an equal number of bacilli can be used and a regular series of specimens 

 obtained. I have found that usinu- two-fifths Of a minim containing one bacillus 

 and keeping the specimen at •".»; ('.. the earliest appearance of spore formation 

 was evident in forty-one hours. 



Leaving these matters, which are of great interest not only in regard to the 

 Bacillus alvei, but to all spore-hearing bacteria, and which I have therefore 



