450 SCIENCE PROGRESS. 



each process clothed with minute cells eager to eat up any 

 foreign matter which comes in its way, the whole forming 

 a simple but apparently very efficient lymphatic gland. 

 Whether these cells have a more intimate relation with the 

 excretory canals on which they are situated, and whether 

 the minute cellules which clothe them are not the corpuscles 

 of the perivisceral fluid, temporarily come to rest, are at 

 present speculations which it is to be hoped further investi- 

 gation will clear up. 



The last Numbers of the Studies from the Zoological 

 Laboratory of Nebraska (Nos. 24 and 26) published under 

 the direction of the eminent helminthologist, Henry B. 

 Ward, contains an interesting summary of the number of 

 parasites found in a given number of cats and dogs exa- 

 mined in the town of Lincoln, Nebr. Two of the parasites 

 of the cat Dipylidium caninum — also found in the dog — 

 and a Distomum, Distomum felinum, have been found in 

 man. The latter is not uncommon in the peasants of 

 Siberia, the former is, however, rare, and is as a rule confined 

 to children of immature years. There is reason to believe 

 that the second host of D. caninum is the Trichodectes cants, 

 and children possibly become infected with it whilst playing 

 with dogs. 



Ward's investigations on the cat are not so extensive as 

 those on the dog, and are less interesting because similar 

 investigations have not been carried on elsewhere, conse- 

 quently no data exist for a comparison between the number 

 of parasites infesting the cats of the ancient cities of the Old 

 World with those of a comparatively new town like Lincoln. 



The following table compiled by Deffke, with the addi- 

 tion of the results of Sommer's investigations in Washington, 

 D.C., and of Ward's at Lincoln, give some idea of the para- 

 sites of the dog in various parts of the world. The list does 

 not include the Trematode Hemistomum alatum, recorded 

 by Schoene in Saxony and elsewhere, nor does it include 

 insect larvae, Pentastomas or a species of Echinorhynchus 

 found by Ward at Lincoln, in fact it is confined to the two 

 orders, Cestoda and Nematoda. 



