DESCRIPTION OF BACILLUS ALVEI. 31 



the first 28 hours. This led hmi to conclude that the time when 

 spores are produced mi<2;lit depend upon the amount of bouillon used 

 and the number of bacilli present. This caused him to devise a sec- 

 ond method. The second method involved the use of a flask of sterile 

 bouillon, Avhich was inoculated with the vegetative form only of the 

 bacillus. This flask was placed in the incubator for two or three 

 liours that the organisms might diffuse equally throughout. The 

 llask was then shaken, and by means of a s}Tinge gauged on the 

 })iston equal quantities of the medium and bacilli were taken. In a 

 series of preparations thus obtained and kept at 36° C. the earliest 

 appearance of spore formation was evident in 41 hours. 



Cheyne records the fact that the swelling in the rod which takes 

 place is usually near the center, but sometimes nearer an end. This 

 swelling increases in size at its center and gradually fails to take the 

 stain. The capsule of the spore, he states, is apparently formed 

 within the rod and is not the outer part of the rod. In three or four 

 hours after the spore was formed it was either entirely free from the 

 rod, or the rod still inclosed the spore, but was almost invisible. 



Having thus studied somewhat carefuUy the morphology (size, 

 form, and structure) of Bacillus alvei, Cheyne took up the further 

 study of the species to determine its cultural characters, stating at 

 this point, very properly, that the microscope is of little use in deter- 

 mining the relation of the bacillus to foul brood. The technique 

 which he used in making cultures is ver}^ similar to that used in gen- 

 eral bacteriological work at the present time, the chief difference 

 being that now additional differential media are used. 



DESCRIPTION OF BACILLUS ALVEI. 



The following is an abridged description of Bacillus alvei as given 

 by CheAme: 



Occurrence. — Isolated from larvae said by Cheshire to be affected 

 with foul brood. As far as is at present known it has not been found 

 elsewhere. 



Gelatin plates. — Gelatin plates were inoculated by stroking the 

 solidified medium ^^dth the needle. From small masses of growth, 

 which soon form along this line of inoculation, bacilli in Indian file, 

 or two or three side by side, grow out mto the gelatin. These out- 

 growths are not straight, but tend to curve, and at a short distance 

 from the track of the needle they grow round so as to form a circle. 

 From such a circle other fresh circles may be formed. The growth 

 about this line increases, filling up the center of the circle. These 

 circular growths increase and may join one anotlier, forming a curved 

 anastomosis. The gelatin in the immediate vicinity of the growth 



