Johannes Fibiger and Hjalmar Ditlevsen: Spiroptera neoplastica n. sp. 11 



This locality too harboured P. americana in great numbers and it was not diffi- 

 cult to prove, that the muscles of these cockroaches also contained the nema- 

 tode coiled up and placed in the same way as in those originally examined. Con- 

 trolling examination of rats from other localities has constantly turned out negative, 

 so that until now the nematode has not been found in 1025 rats belonging to the 

 species M. decumanus, in 21 rats of the species M. rattus, and in 2 rats of the species 

 M. alexandrinus caught in various localities in Copenhagen and the neighbourhood, nor 

 in 277 black and white or white rats from different laboratories. 



Add to this several rats examined in the Institute the exact number of which 

 can not be accounted for, the nematode was not observed in altogether nearly 1100 

 wild rats and nearly 300 labpratory rats. 



Neither has the nematode been found in other wild cockroaches than in those 

 {P. americana) living in the two refmeries (see further below). 



After all there is great evidence that in this country the nema- 

 tode is bound to such localities (sugar-ref ineries) as contain the 

 P. americana. These localities having in former days received raw sugar from West 

 India where P. americana is very common, it seemed an obvious conclusion that the 

 nematode must be found in the Danish West Indies. A series of investigations has 

 been established and owing to kind assistance by the veterinary surgeon of the govern- 

 ment Selmer, 6 dead rats {M. rattus) and c. 90 live cockroaches {P. americana) were 

 sent to Denmark from St. Croix. Examinations in the anatomical-pathological Institute 

 now showed that the cardiac portion of 2 of these rats contained specimens of the 

 nematode; and in the muscles of 2 out of 6 cockroaches examined, the nematode 

 was also observed. The rest of the cockroaches (84) were used — the ^'^/t 1913 — 

 as feeding material on black and white normal laboratory rats, 6 out of which died 

 resp. 18, 30, 44, 79, 85 and 141 days after the feeding. 



In the epithelium of the cardiac portion of the stomach typical Spiropteræ were 

 found in all the rats, in one, moreover, typical papillomatous growth of the same type 

 as described above. One rat is still alive and infected, typical eggs having been found 

 in his fæces. Thus, it must be considered very probable, that the Spir- 

 optera in question originally was imported to Denmark with P. americana 

 in the raw sugar from the Danish West Indies. 



A series of investigations has further been carried out in order to transmit the 

 nematode to other . rodents. As already mentioned in a former paper it did not 

 cause any difficulty to transmit the nematode to mice. Up till now^) the experi- 

 ments completed comprise 61 mice, all of which were infected on feeding with cock- 

 roaches containing the Spiroptera. In 31 mice out of the same stock which had not been 



'') December 1913. 



2* 



