64 LINES OF INVESTIGATION IN DISEASES 



the development of intestinal toxemia in chickens is through the presence of 

 intestinal parasites. And so, in leg weakness or rheumatism or paralysis 

 or whatever you choose to call it, purgation results in a most beneficial 

 confirmation of the diagnosis. 



The bacterial diseases of chicks demand investigation. Shortly after 

 the appearance of Circular 128, Rettger and Harvey presented a detailed 

 study of a speticemia of young chicks which had been studied earlier by 

 Professor Rettger himself. The authors have seen fit to attach to their 

 title the words "White Diarrhea" although the disease bears all the ear 

 marks of a septicemia. For this reason and because diarrhea is apt to be 

 one of the symptoms of the young chick's infection with this bacterium 

 discovered by Professor Rettger, the disease calls for mention at this point. 

 It seems to the writer that nothing could offer a more interesting and fruit- 

 ful field of investigation than a most careful study of the bacterial flora of 

 the fowl's intestine, starting, of course, with the chick. Those who enter 

 deeply into the microbiologic investigation of chick diseases will find, as has 

 the writer, that various bacteria play a part in the production of death even 

 when the diseased condition has been induced by coccidia, flagellates or 

 worms. This is true not only for chicks but also for fowls. Hence the 

 importance of a knowledge of the bacteria that are likely to come to light 

 from time to time in connection with these different ailments, for instance, 

 Bacillus coli, Bacterium aerogenes, Bacterium sanguinarium Moore, the 

 bacillus of fowl cholera, Bacillus pyocyaneus otherwise known as the bacillus 

 of green pus, and some of the variants of Bacillus proteus. 



The molds that produce disease in chicks should be studied. It is 

 probable that but one, Aspergillus fumigatus, calls for special study. This 

 is known to be quite troublesome especially among water birds and pigeons. 

 The writer within the last few months in attempting to distinguish between 

 the various diarrheas of chicks has come to recognize that what is called 

 "pasting" or "pasting up behind" is oftener associated with a lung affection 

 than with coccidiosis, although it may occur in this latter disease. Brooder- 

 pneumonia or, as it is sometimes called, incubator penumonia is an affection 

 of young chicks in which the lungs are studded with pinhead yellowish or 

 whitish nodules. Sometimes a large portion of one or both lungs are trans- 

 formed into a cheesy mass. Such chicks have been called "lungers." This 

 lung disease according to the writer's findings is due to the presence of the 

 mold, Aspergillus fumigatus. The recognition of this organism in this 

 affection and the development of the disease at such an early date suggests 

 also the possibility of egg infection from the hen's diseased eggtube or by 

 being retained for some time in a musty locality before incubation. It has 



