Apkil 11, 1913] 



SCIENCE 



517 



assistant chief, Bureau of Highways and Street 



Cleaning, Philadelphia. 



Bead by title. 

 The Mixing Plants Used in the Construction of 



the TopeTca Bituminows Concrete Pavements of 



the Borough of Queens in 1912: A. F. Geuen- 



THAL, assistant engineer. Bureau of Highways, 



Borough of Queens, N. Y. 



Read by title. 

 Bituminous Gravel Concrete Pavements: Spenceb 



J. Stewart, division engineer, New York State 



Department of Highways, White Plains, N. Y. 



This pavement consists of mixing Hudson River 

 eementatious gravel, heated to a temperature of 

 over 225 degrees F., with natural lake asphalt 

 heated to a temperature of not less than 275 

 degrees F., thfen placing both ingredients in a 

 mechanical revolving mixer and thoroughly agi- 

 tating until all the particles of the mineral aggre- 

 gate are thoroughly and completely coated with 

 the bituminous material. 



This mixture, at not less than 250 degrees F., is 

 then spread upon the prepared bottom or founda- 

 tion course. 



The gravel is composed of calcareous sandstone, 

 granite and quartzite, associated with a consid- 

 erable amount of finer particles of the above- 

 named rocks, together with a percentage of clay. 

 This latter substance gives the gravel a good 

 cementations value, which is an essential to the 

 comparative permanency of the pavement. The 

 clay acts as a catalyzer on the asphalt, making it 

 more viscous, less volatile and also less brittle. 



The advantages of this pavement are: 



First, its comparatively low cost over so-called 

 semi-permanent pavements. 



Second, on account of its adaptability to coun- 

 try and parkway purposes, due to its easy riding 

 surface and its conformity to our ideals of the 

 surroundings of a parkway or country highway. 



Third, on account of its non-slippery nature, it 

 being practically a "non-skid" road. 



From the contractor's bids, the average cost of 

 this pavement is about $0.85 per square yard. 

 A Review of the TJse of Bituminous Materials in 



the Construction and Maintenance of American 



Sighways during 1912: Arthur H. Blanchard, 



professor of highway engineering, Columbia 



University, New York City. 



G. W. BiSSELL, 



Secretary 

 East Lansing, Mich., 

 March 10, 1913 



SOCIETIES AND ACADEMIES 



THE HELMINTHOLOGICAL SOCIETY OF WASHINGTON 



The fifteenth regular meeting of the society 

 was held at the residence of Dr. Ransom, March 

 20, 1913, Dr. Ransom acting as host and Mr. 

 Chambers as chairman. 



The comparative anatomy of the free-living and 

 the parasitic nematodes was discussed by the 

 society. 



Mr. Crawley presented a note reviewing Muriel 

 Robertson's work on Trypanosoma gambiense and 

 its vector, Glossina palpalis. She has shown there 

 is a rhythmic cycle in the life of the trypanosome 

 in the vertebrate host, the parasite falling off in 

 numbers at times until there are only a few small 

 forms present, which then begin to multiply with a 

 resultant production of larger forms until the 

 blood contains numerous large forms, and the 

 cycle repeats. An endeavor to correlate this alter- 

 nation of few small forms and numerous large 

 forms with the infectivity of the trypanosomes 

 for its invertebrate host, the tsetse fly, developed 

 the fact that the infectivity was at its maximum 

 when the few small trypanosomes were in the blood 

 and at its minimum when the many large forms 

 were present. 



Dr. Ransom presented a note on ' ' The Re- 

 ported Hosts of Cysticercus cellulosw." It is 

 commonly stated in general works on parasitology 

 that Cysticercus cellulosce occurs not only in the 

 pig, its usual host, and in man, a not uncommon 

 host as a result of auto-infection, but also in the 

 dog, cat, bear, sheep, deer, rat and monkeys. It 

 has also been reported from a seal. 



The only hosts, however, in which the occurrence 

 of Cysticercus celluloses can be considered to have 

 been proved are the first three named. The re- 

 puted occurrence of C. cellulosw in the cat, bear, 

 rat and seal rests apparently upon a single in- 

 stance of the discovery of cystieerci resembling 

 C. cellulosw in these hosts without proof by feed- 

 ing experiments. Likewise, though several cases 

 of C. cellulosw have been reported from monkeys 

 and rather many eases from sheep and deer, no 

 experimental proof or other evidence of a con- 

 elusive nature that the parasites in question were 

 really C. cellulosw has been furnished. On the 

 contrary, the evidence thus far available tends to 

 prove the non-occurrence of C. cellulosw in these 

 animals, particularly in the case of sheep and 

 deer. It has, in fact, been recently shown (Ran- 

 som, 1913) that the muscle cysticercus of sheep 



