NA TURK 



97 



THURSDAY, DECEMBER 4, 1884 



THE CHOLERA BACILLUS 

 T N view of the investigations which are going on at the 

 present time, it will be of interest to our readers to 

 summarise the reasons which Koch gives for his conclu- 

 sion that the comma-bacilli described by him are the 

 cause of cholera. No doubt can remain in the minds of 

 those who have read his paper on the subject, published 

 in the Berl. Klin. Wochenschrift, No. xxxi., 1884, and the 

 discussion thereon, that he has devoted an immense 

 amount of time and labour to the question, and that he 

 has dealt with the subject in a most open-minded and 

 conscientious manner. His known character for accurate 

 observation and care in drawing conclusions lend great 

 weight to his statements. We will give a short sketch of 

 his arguments under a series of headings. 



(1) The comma-bacillus is a specific micro-organism 

 having marked characteristics distinguishing it from all 

 other known organisms. 



Their length is from half to two-thirds of that of tubercle 

 bacilli, but thicker and slightly curved : this curve is 

 generally not more than that of a comma, but sometimes 

 it may be greater, forming even half a circle. Sometimes 

 several bacilli can stick together end to end, giving rise 

 to the appearance of a spirillum. Koch thinks that this 

 organism stands midway between a bacillus and a spiril- 

 lum. They grow rapidly in meat infusion. They possess 

 the power of active motion. They also grow well in other 

 fluids, in milk more especially. They increase rapidly in 

 blood serum. A very good medium is Koch's gelatinised 

 infusion (peptone, gelatine, meat infusion, made neutral 

 by carbonate of soda), and its cultivation in this material 

 "renders its detection easy and very certain." Shaken 

 up with the liquefied gelatine, poured out on a sterilised 

 glass plate, and kept at a temperature at which the gela- 

 tine becomes solid, its colonies are very characteristic : 

 when young, they appear as small, very pale drops, not 

 quite round, but more or less irregular and jagged in 

 contour ; they also have a granular appearance, and 

 when larger look like a heap of strongly-refracting pieces 

 of glass ; the gelatine becomes fluid in the immediate 

 neighbourhood of the colony, the latter sinks into the 

 gelatine, and thus a small funnel-shaped depression is 

 formed, in the middle of which the colony is seen as a 

 small white point. The liquefaction of the gelatine does 

 not extend more than about one centimetre around the 

 colony. If a tube of solid gelatine is inoculated by 

 dipping a needle in the cultivation, and pushing it into 

 the gelatine, the latter becomes fluid first at the point of 

 entrance of the needle ; the colony sinks more and more ; 

 a funnel-shaped depression is formed with an appearance 

 as if an air-bubble were present at the top. They can 

 also be cultivated in a meat infusion containing peptone, 

 neutralised and rendered solid by agar-agar. They grow 

 on potatoes, forming colonies closely resembling those of 

 the bacillus of glanders, but not so brown as the latter. 

 They grow best at a temperature between 30 and 40 C. ; 

 below 1 6° C. they cease to grow ; freezing does not kill 

 them. They only grow in presence of oxygen. They grow 

 very fast ; their vegetation rapidly reaches its highest 

 Vol. xxxi. — No. 788 



point : it remains stationary for a time, and then as 

 rapidly ceases, the bacilli dying. They will not grow in 

 meat infusion or the gelatinised material if it is at all 

 acid. They die very rapidly when dried, not retaining 

 their vitality longer than three hours. They do npt form 

 spores, corresponding in this respect with spirilla rather 

 than with bacilli ; Koch has made an exhaustive series of 

 investigations to ascertain this point. Micro-organisms 

 presenting all these characteristics are the bacilli de- 

 scribed by Koch ; organisms presenting only some of the 

 characteristics, such as microscopical appearance, but 

 differing in other points, are not Koch's comma-bacilli. 



(2) This bacillus is always present in cholera. 



Koch states that this bacillus is always present in cases 

 of cholera. He determines its presence not only by micro- 

 scopical examination, but by cultivation in gelatinised 

 meat infusion. In ten cases in Egypt they were found 

 microscopically (he had not then worked out their 

 characteristics on cultivation). In India he made forty- 

 two post-mortem examinations, and found them in all 

 cases, by cultivation and microscopical examination, in 

 the intestinal canal. The dejections of thirty-two cholera 

 patients were also examined in the same way, and the 

 comma-bacilli were found in all cases ; also, in two cases 

 seen in Toulon, and microscopically in sections of the 

 intestinal wall in eight cases sent to him previously from 

 India and Egypt. In almost 100 cases carefully examined 

 these organisms were found, and that in cases occurring 

 in various parts of the world. 



(3) It is the only form which is constantly present in 

 this disease. 



(4) It is present in greatest numbers in acute and 

 uncomplicated cases. 



Koch has found that this is the case, and that on the 

 other hand, in cases which live longer, the bacilli are 

 fewer, and more especially where haemorrhage or other 

 complications have occurred, other bacteria are most 

 numerous. 



(5) It is present in the parts most affected. 

 According to Koch the lower part of the small intestine 



is that most affected by the disease, and here the bacilli 

 penetrate into the tubular glands and also in part between 

 the epithelium and basement membrane ; in some places 

 they penetrated even more deeply into the tissue. Where 

 death of portions of the mucous membrane had occurred, 

 other bacteria were also present in the tissue, but the 

 comma-shaped ones were always deepest, "giving the 

 appearance as if they had prepared the way for the 

 others." 



(6) It is never present in other diseases, in healthy 

 persons, nor has it been found outside, the body when no 

 cholera was in the neighbourhood. 



This is the keystone of the research, and naturally Dr. 

 Koch has devoted great attention to this point. All his 

 investigations in this direction have been carried out by 

 his usual methods — chiefly by cultivation, aided also by 

 the use of the microscope. He has thoroughly examined 

 thirty bodies of patients who had died of dysentery, 

 intestinal catarrh, " biliary typhoid," one case of ordinary 

 typhoid fever, and several cases where ulceration of 

 the intestines has been present. In none of these did he 

 find comma-bacilli. He failed to find them in a number 

 of cases where he examined the dejections of patients 



