172 Phylum N emathelminthes 



The amount of dilute formalin that may be added to inhibit fungous 

 growth depends upon the permeability of the egg envelopes, which differ 

 in the various species of nematodes. 



THE LIFE HISTORY OF THE SWINE KIDNEY WORM* 



UNDER laboratory conditions, at a temperature of about 2 6° to 

 2 7 C, the preparasitic stages of the development of Stephanurus 

 dentatus were completed in from 5 to 6 days. Eggs obtained from gravid 

 females and cultured in water or on a charcoal and feces mixture 

 hatched in from 24 to 48 hours, and the larvae reached the first lethargus 

 about 24 hours after hatching. The second lethargus was reached about 

 48 hours later, and the infective stage, that of the third stage larva, was 

 usually attained about 24 hours after the onset of the second lethargus. 

 Low temperatures have been found to retard the development of the eggs 

 and larvae, and at temperatures sufficiently low not only was development 

 arrested but the vitality of the eggs and larvae was destroyed. 



When infective larvae of S. dentatus were placed on the scarified skin 

 of pigs or when they were injected subcutaneously infection resulted, the 

 course of development being similar to that which followed the adminis- 

 tration of larvae by mouth. 



Stephanurus has been reared experimentally in guinea pigs in which 

 animals they have been found to attain a considerable growth and 

 development. 



M. E. D. 



Family oxyuriformidae 



CULTIVATION OF A PARASITIC NEMATODE 



William Trager, Rockefeller Institute for Medical Research 



THE nematode parasite (Neoaplectana glaseri) of the Japanese beetle 

 (Popillia japonica) was cultured by Glaser (1931, I93 2 )- Plates of 

 the culture medium are prepared by mixing in a sterile 5M>-cm. petri dish 

 about 8 cc. of melted veal infusion agar (pH 7.4) with 2 cc. of a 10% 

 dextrose solution. The surface of the cooled medium is flooded with a 

 concentrated water suspension of a pure culture of baker's yeast and the 

 plate is incubated 24 hours at room temperature. The yeast growth 

 inhibits later bacterial growth and serves as food for the nematodes. 

 These are obtained from diseased Japanese beetle grubs and, after having 

 been sedimented and washed three times in water, are placed on the yeast- 

 culture plate. The culture is incubated at room temperature. 



♦Abstracted from an article in Science 70:613, 1929, by Benjamin Schwartz, U. S. 

 Bureau of Animal Industry. 



