546 EXPERIMENT STATION RECORD. [Vol.40 



varies with the species attacked, and may result In early defoliation and a 

 consequent poor crop, hut in general it is not serious on this host. 



New researches on the variability of plantation Para rubber, B. J. Eato:; 

 (Jour. Soc. cinin. Indus., 86 (1917), No. 23, pp. 1211-1226).— In connection 

 with a large body of observations and deductions on other phases of rubber- 

 curing technique, the author states that the formation of pigment, which is 

 known as spot disease of rubber, requires the presence <>f moisture and air or 

 oxygen for the development of the spores. The development of the organisms 

 on a slow-curing crepe rubber lias little or no effect on its vulcanizing capacity 

 In respect to its rate of curing, since thin crepe contains none of the vulcaniza- 

 tion accelerator present in slab crepe. Such development of microorganisms in 

 slab cr§pe causes a marked retardation In the rate of cure, due supposedly to the 

 utilization or alteration of the accelerator by the organisms. During the de- 

 velopment of spot disease, a loss in gaseous form occurs of some constituent at 

 present unknown. The antiseptic effect of smoke (that from coconut husks, for 

 example, containing creosote products) retards, while high temperature accel- 

 erates, the rati- of curing. 



ECONOMIC ZOOLOGY— ENTOMOLOGY. 



The rodents of Iowa, D. Brown (/OfOS <!<nl. Survey Bui. 5 (1918), pp. 112, 

 fins. 36). — An account of '.<\ species of rodents occurring in Iowa, of which the 

 pocket gopher (Oeotny$ burtariut bunarimt) is the most destructive, being 

 responsible for an annua] loss estimated n< :i half million dollars. Keys for the 

 separation of the genera and species, a list of 10 references to the literature, 

 and a subject lodes are Included. 



The rat. — Reference tables and data for the albino rat (Mus norvegicus 

 albinus) and the Norway rat (M. norvegicus), II H. 1 »o\ m doom i Mem. Wi$Un 

 hist. Anat. and Biol., No. 6 (1915) w<. P+878, flea St) The Introductory part 

 of this work treats of the rat a> a laboratory animal. Indicates the methods of 

 gathering the data here pi and also gives examples of the use of the 



tables. An outline of the classification and early records and migrations of the 

 common rats are also Included. Pari l (pp 19 i V| ">i deals with the biology, 

 heredity, anatomy, physiology, and growth of the domesticated albino rat; and 

 part "J (pp. 189 213), with the life history, distinguishing characters, and growth 

 Of the Wild Norway rat. 



A 58 lisl of references to the literature and a subject index are Included. 



The rat and infantile paralysis. — A theory. If, W. RlCHABSBOK (Aimer, 

 Jour. Pub. Health, 8 (1918), V« S, pp. ■',>:; 579, fig* ff).- The data presented 

 in this second contribution (B. s. \i. 86, p 854), which are based particularly 

 upon observations made during the epidemic In New York t'ity in 1916, have 

 ifii to the follow lug conclusions : 



"Although the %ini^ of Infantile paralysis has been demonstrated m the 

 secretions and excretions of persons si.-k with the disease and healthy third 

 persons who have or have not been In contact with patients, and although such 

 secretions and excretions may In animal experiment remain active for many 



months, the epidemiological facts are strongly against the ti ry that infantile 



paralysis is spread from person bo person by direct or Indirect contact <>n the 

 other hand, the epidemiology of infantile paralysis corresponds so remarkably 

 with that of bubonic plague, a disease known to be due t<> the rat and flea, that 



It CSS be stated with great probability that human Infantile paralysis is due to 

 a precedent and underlying infection of rodents. 



" As with bubonic plague, final proof a-- to the rOle of the rat and Ilea in 

 infantile paralysis must rest in elaborate laboratory Investigation." 



