REPORT OF THE COMMISSIONER OF FISHERIES. 117 



sewage bacteria (Bacillns eoli, the type form) normal ami usual inhabitants of shell- 

 li.sh? (2) How soon after the introduction of B. coli into the water does it appear in 

 the clam? (3) How long does B. coli live in ordinary sea water? (4) How long, 

 under normal conditions, does B. coli remain alive and active in the intestine of shell- 

 fish? (5) Is it probable that the shell-fish digest B. coli and thus incidentally act as 

 purifiers of the sewage-polluted waters, and further, that by digesting B. coli, shell- 

 fish may after a time become free from sewage bacteria and therefore harmless as 

 food for man? (6) Examination to ascertain what anatomical region is most certain 

 to give a true index to the presence of B. coli. 



The methods usetl bj^ Doctor Field and Doctor Fuller for securing proper conditions 

 of infection with Bacillus coli and for maintaining the normal conditions of life for 

 the clams proved satisfactory. The results will probably be published by the 

 Massachusetts State Board of Health in its annual report and are believed to be of 

 considerable importance. 



The lobster problem. — At the request of Capt. J. W. Collins, chairman of the fish 

 and game commission of Massachusetts, Doctor Field secured at Woods Hole and 

 Cuttyhunk important data concerning the lobster industry, bearing upon the biological 

 importance of preserving the adult lobsters and permitting the catching of immature 

 ones. Figures were obtained indicating the commercial value, in terms of edible 

 meat, of lobsters 8.5, 9.5, and 10.5 inches long; also the weights and measurements 

 (length, weight, and diameters of chela?, thorax, and abdomen) of upward of 800 

 newly caught lobsters coming from different sections; and some observations were 

 made upon the relative numbers of mature and immature lobsters in the ocean. In 

 connection with the recommendatioji of a law which would insure the perpetual 

 protection of the adult lobster, experiments were made looking toward the adoption 

 of a pot Vt^hich would exclude lobsters above 11 inches in length and permit the 

 escape of those under 9 inches. The result of this would be the automatic regulation 

 of lobster catching to practically only those sizes between 9 and 11 inches. 



The food of murine birds. — Lynds Jones, M. S., instructor in zoology, Oberlin Col- 

 lege. These investigations were made on AVeepecket, Penikese, and Muskeget 

 islands. Stomachs of young terns were examined, and the feeding of the young by 

 the parent, as well as the feeding of the adult birds, was carefully noted. Mr. Jones 

 gives the following estimate of the tern population of the various islands where they 

 nest: Weepecket, 2,000; Penikese, 10,000; Muskeget, 80,000; total, 92,000. The two 

 species {Sterna hirundo and ,S. dougalli) are represented in about the proportion of 2 

 to 1. The feeding habits and the food of the two are the same. The number of 

 fishes eaten in this region by terns in the course of one day is estimated by Mr. Jones 

 as follows: Sand launce {Anirnodijtes amexicanus) , 736,000; chogset [Tautogolahrus 

 adspersus), 73,600; mullet {Mugil curcma), 36,800; pollock {PoUachias rirens), 27,600; 

 clupeid fish {Clupea or Pombolobus) 27,600, and flounder { Pseiulopleuronectes ameri- 

 canus), 18,400. Mr. Jones concludes that the number of food fishes consumed by 

 terns is a negligible quantity. The food of the gulls, loons, kingfishers, osprey, and 

 ducks was not studied. 



The bactericidal properties of sera of marine animals. — G. F. Kuediger, M. D., Memo- 

 rial Institute for Infectious Diseases, Chicago (Rush Medical College). The object 

 of this work was to find a n(jrmal blood serum in cold-blooded animals which would 

 be destructive to streptococci. Sera from butter-fish, dog-fish, conger eel, flounder, 

 mackerel, dusky shark, sand shark, scup, squeteague, butterfly-ray, sting-ray, com- 

 mon skate, squid, lobster, spider crab, king crab, snapping turtle, painted turtle, and 

 spotted turtle were used. Streptococci were found to grow well in all of these sera, 

 excej^ting those of the painted turtle and spotted turtle. These two sera seemed to 

 kill large numbers of organisms from some cultures of streptococci, other cultures, 

 however, not being affected. Heating the serum destroyed its bactericidal prop- 

 erties. An attempt was also made to immunize the dog-fish, but lack of time pre- 

 vented conclusive results. 



