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support of the fact that not all persons taking poisonous milk suffer 
equally, and some escape altogether. 
The endotoxines and bacterial proteids are poisonous substances 
which are more or less firmly retained by the living bacterial cells. 
The poisonous action of these so-called “ toxines ” is closely associated 
with the phenomenon of anaphylaxis.® We are not yet sufficiently 
well acquainted with the composition and mode of action of this im- 
portant class of poisons to formulate their relation to milk. 
The colon group. — The type of this large group of bacteria was 
first described by Escherich as Bacillus coli commune. While the 
colon bacillus is undoubtedly the cause of certain pyogenic and septi- 
cemic conditions, its power to produce harm in milk is uncertain. 
Normally it is practically always present in the lower intestines of 
mammalian animals, where it doubtless serves a useful purpose per- 
haps by keeping in check other harmful varieties. 
The colon bacillus was at one time regarded as the common cause 
of various diarrheal infections, but it has now been differentiated into 
the dysentery bacillus, the typhoid bacillus, and other closely allied 
species. Even now it is difficult to disassociate its action from that of 
its closely allied cousin, the B. lacticus aerogenes. These two organ- 
isms sometimes induce excessive fermentation of lactose and other 
sugars with the production of irritating acids (especially acetic and 
lactic) and at the same time liberate an excessive amount of gas, 
thereby causing diarrhea. 
The typhoid bacillus. — It is known that this bacillus often con- 
taminates milk which thus becomes the vehicle of some of the typhoid 
fever in large cities. The paratyphoid and paracolon organisms are 
closely allied and may doubtless be transmitted in like manner. The 
paratyphoid bacillus is a frequent cause of meat poisoning, but a 
similar action in milk has not been shown. 
The dysentery bacillus . — Shiga, who discovered this organism, 
now recognizes 5 types, based on fermentative changes. This 
organism, like the typhoid bacillus, is “ hemiparasitic ” in the sense 
used by Herter; that is, it produces disease only when the bacilli 
have been introduced in considerable numbers or have had an oppor- 
tunity to multiply owing to the feeble powers of resistance on the 
part of the infected individual. 
® Rosenau, M. J., and Anderson, John F. : A study of the cause of sudden 
death following the injection of horse serum. Bull. No. 29 Hyg. Lab., U. S. Pub. 
Health & Mar.-Hosp. Serv., Washington, 1906. 
Rosenau, M. J., and Anderson, John F. : Further studies upon hypersuscepti- 
bility and immunity. Bull. No. 36 Hyg. Lab., U. S. Pub. Health and Mar.- 
Hosp Serv., Washington, 1907. 
