672 



SCIENCE 



[N. S. Vol. XXXVIII. No. 984 



aerobic cultures of Bacillus coli. This throws 

 additional doubt upon the reliability of gas 

 determinations made by the methods in com- 

 mon use. 



Based largely upon his results with the Dur- 

 ham tube, Penfold at one time or another has 

 come to the following conclusions : 



It may be suggested, therefore, that . . . the 

 selective process has caused the removal of the 

 formic-acid-forming ferment, but apparently has 

 not interfered with the formic-acid splitting fer- 

 ment.i* 



The power of gas formation from sugars (always 

 excepting isodulcite) may be lost when gas forma- 

 tion from alcohols is retained. It is probable, 

 therefore, that two different ferments are engaged 

 in the respective processes.is 



The research raises the question as to the weight 

 to be attached to the power of fermenting glucose 

 and lactose with gas formation in recognizing B. 

 coli in routine examinations of pathological ma- 

 terial, water, foods, etc. Hitherto, in all authorita- 

 tive catalogues of the necessary properties of this 

 organism, this has been included, but it probably 

 ought not to be regarded as absolutely essential.is 



Perhaps more exact work will demonstrate 

 the essential truths there may be in these 

 statements. If so, it will in no wise alter the 

 contention of this article, which is that con- 

 clusions of such profound importance are 

 worthy of being established by methods of 

 reasonable accuracy. 



It is gratifying to learn that Harden and 

 Penfold have set out to do so. Pending the 

 fuller publication of their results this article 

 would not have been written but for the fact 

 that Penfold since the publication of the pre- 

 liminary report of Harden and Penfold, has 

 published another paper,^' in which he seems 

 to have missed the significance of the discrep- 

 ancy between his earlier statement that the 

 variant colon produces no gas from dextrose, 

 and Harden and Penfold's later statement that 

 it does. 



14 Penfold, W. T., Proceedings Royal Society of 

 Medicine, Pathological Section, Vol. 4, Part 3, p. 

 106. 



15 Penfold, W. T., Journal of Hygiene, Vol. II., 

 p. 502. 



i« Penfold, W. T., ihid. 



17 Journal of Hygiene, April, 1913. 



Unfortunately Penfold is not alone in the 

 false confidence he has placed in the reliability 

 of the Smith and Durham tube methods of 

 bacterial gas determination. These instru- 

 ments, which are useful only in the routine 

 laboratory, are still being widely used in ela- 

 borate researches; and the time, therefore, 

 seems ripe to emphasize the errors to which 

 their use may lead, and to plead for greater 

 accuracy in this important test of bacterio- 

 logical chemistry. Wm. Mansfield Clark 



Washington, D. C. 



SPECIAL ARTICLES 



A NEW MEANS OP TRANSMITTING THE FOWL 

 NEMATODE, HETERAKIS PERSPICILLUM 



It has been found that Heteralcis perspi- 

 cillum may be transmitted to young chicks by 

 a dung eai'thworm found in horse manure. 

 The earthworm in question is probably Helo- 

 drilus parvus (Eisen).^ The experiment 

 demonstrating this relationship was per- 

 formed during the past summer at the Kansas 

 State Agricultural College. Eleven chicks, as 

 soon as hatched, were placed in a fly-proof 

 field cage and kept there until the close of the 

 experiment. The cage was so constructed that 

 the chicks could not reach chance insects that 

 happened to light upon the outside screen. It 

 had two fly-proof doors enclosing an entry 

 way and the outer door was kept locked. When 

 entering the cage the outer door was closed 

 and the entry inspected for chance flies be- 

 fore opening the inner door. On leaving the 

 pen the same care was taken. All chicks were 

 thrifty and were fed upon the same ration of 

 dry food to which was added twice per day 

 some green alfalfa. It is needless to say that 

 the alfalfa was always examined to prevent 

 any insects from entering the pen. The 

 earthworms were fed to three of the chicks. 

 To the first chick a total of 78 worms was fed 

 in lots of six to twelve each day between July 

 17 and July 26, inclusive. To the second 

 chick 64 were fed, July 18 to July 29. The 



1 The earthworm mentioned has been referred to 

 Professor Frank Smith, University of Illinois, for 

 identification, and the nematode has been verified 

 by Dr. Albert Hassell, Division of Zoology, B.A.I., 

 Washington, D. C. 



