162 EXPERIMENT STATION RECORD. 



Experiments in the use of sheep in the eradication of the Rocky Moun- 

 tain spotted fever tick, H. P. Wood {U. S. Dept. Agr. Bui. 45, pp. 11). — This 

 is a report of experiments conducted to determine the value of sheep in de- 

 stroying Dermacentor venustus as brought to attention by L. D. Fricks in an 

 article previously noted (E. S. R., 29, p. 658). 



Two experiments, the first with 20 sheep, the other with 2 sheep, were 

 carried through. The first was conducted in a country known to be well 

 infested with ticks, being adjacent to the foothills and well supplied with 

 bushes of various sorts, a growth of small pines, a few fairly large trees, 

 and several streams of water. The conditions were such that there could 

 have been few, if any, ticks on the sheep at the time they were driven into 

 "ticky" country. During the course of the experiment, which was com- 

 menced on June 3, two thorough examinations were made, commencing June 

 10 and 23, respectively, of each sheep to locate the living ticks and to remove 

 the dead ones. Numerous other, but less thorough, examinations were also 

 made, when any dead found were removed and the living ones noted. In 

 the second experiment ticks were collected by dragging cloths over the gr(fund, 

 and then placed upon the sheep — on the first June 20 and on the other June 

 25, the examinations also being made twice a day. The details of the results 

 are presented in both tabular and descriptive form. 



The experiments show that sheep are good collectors of ticks, 6 sheep with 

 heavy wool having picked up 72 females and 47 males in 11 days. Thus in 

 " ticky " country which is favorable to the herding of sheep it would be advan- 

 tageous to use them as collectors of ticks, since by dipping the sheep once in 

 7 days it would seem that much good could be accomplished. In order to bring 

 about the greatest good it would be necessary to herd the sheep with a knowl- 

 edge of the location of the ticks, since it is extremely doubtful if they would 

 be of much importance as collectors of ticks if allowed to run free. Of 33 

 female ticks placed upon a sheep in the second experiment but one fed sufli- 

 ciently to lay eggs. There were in all, however, 6 females which stood a fair 

 chance of engorging, so that it is difiicult to say what percentage of females 

 that get on a sheep in nature will engorge to repletion. 



Several limitations to the practicability of using sheep exclusively in the 

 eradication of the spotted fever tick, namely, (1) the necessity of eliminating 

 all other live stock except that on which the ticks could be destroyed at weekly 

 intervals by dipping or otherwise; (2) the impracticability of heavily stocking 

 a given area with sheep and attempting to carry the usual number of other 

 live stock on the same pastures; and (3) the necessity of cutting down all 

 vegetation higher than a sheep's back, emphasize the great importance of fol- 

 lowing the plan of dipping domestic animals which is successfully under way. 

 Thus while sheep may be used under some conditions of the work, the main 

 reliance must be upon the dipping of horses and cattle. 



FOODS— HUMAN NUTRITION. 



Bouillon cubes — their contents and food value compared with meat ex- 

 tracts and homemade preparations of meat, F. C. Cook [U. 8. Dept. Agr. Bui. 

 27, pp. 7, figs. 10). — The composition and nature of commercial bouillon cubes 

 are discussed on the basis of analytical data, in comparison with commercial 

 meat extracts and similar preparations and homemade broths and soups. 



The author's summary follows. 



" One-half to three-fourths of bouillon cubes is table salt. The cubes are not 

 concentrated beef or meat essence, as many people believe. They are valuable 

 stimulants or flavoring agents, but have little or no real food value. Bouillon 

 cubes, therefore, are relatively expensive. 



