Ascaridae 171 



Since at ordinary room temperature the ova do not hatch for an addi- 

 tional 36 hours, there was a heavy growth of bacteria in the cultures by 

 the time the larvae were ready to begin feeding. The sterile ova were in- 

 troduced into the flasks in 1 cc. portions of an aqueous suspension, several 

 thousand ova usually being put in each flask. 



In experiments so far carried out larvae have grown to the infective 

 stage in the normal period of about 7 days on pure cultures of Bacillus 

 coli, B. subtilus, B. prodigiosus, B. lactis aerogenes, Staphylococcus au- 

 reus, Spirillum metchnikovi, S. rubrum, and Micrococcus citreus. Ova 

 which were put on plain agar without bacteria hatched normally and lived 

 for as long as ten days, but did not grow. If bacteria were then introduced 

 into the flasks, the larvae grew to the infective stage. 



Not all bacteria are suitable food for hookworm larvae, since they 

 failed to grow on cultures of Bacillus pyocyaneus and Sarcina lutea, and 

 growth was very much retarded on cultures of B. cereus and B. mega- 

 therium. Larvae, however, grew normally on a mixed culture of Bacillus 



cereus and B. coli. 



Bibliography 



Looss, A. 191 1. The anatomy and life history of Anchylo stoma duodenale Dub. 

 Part II. The development in the free state. Reeds, of Egypt Govt. Schl. of Med. 

 4:163. M. E. D. 



Family ascaridae 



CULTURING EGGS OF THE FOWL NEMATODE, 

 ASCARIDIA LINEATA 



J. E. Ackert, Kansas State College 



THE eggs may be secured from either live or dead worms, but cul- 

 tures from live worms are much to be preferred. The anterior end 

 of the worm is excised and the internal organs pressed into a sterile 

 petri dish ; the uteri are isolated and transferred to another sterile dish. 

 At various points the uteri are punctured for the liberation of eggs with 

 characteristic light centers which are known to be fertile. The portions 

 of uteri containing fertile eggs are transferred to a final sterile petri dish, 

 and the eggs pressed out and covered with sterile distilled water. To 

 prevent bacterial or fungous growth 4 or 5 drops of 2% formalin are 

 added. The cultures are incubated approximately 3 weeks at 27 to 

 30° C 



For best results the culture dishes should be opened daily and agitated 

 to facilitate entrance of oxygen. If patches of fungus appear they 

 should be removed. As the eggs usually adhere to the bottom of the 

 dish, the medium must be poured off and a new supply added. 



