PROGRESS IN BIOLOGICAL INQUIRIES, 1921. 
REPORT OF THE DIVISION OF SCIENTIFIC INQUIRY FOR THE FISCAL YEAR 1921.’ 
By R. E. CoKeEr,’ 
Assistant in Charge of Scientifie Inquiry. 
CONTENTS. 
Page 
TEEeU TT COG DLE C0 a bee ees ha a ie i a pS wa nD 
SHILCICSEOR USC Gan meee ee ote Se SE ee ee 5 
RRC RAEI Gwe Mees eee eee ee Fe a ae ee 5 
Immature isalmontinatheroceany 4)» 298s ye 6 
Resultsiok markino: experiments 2 = 2 7 
SHIMON VESTN LION: in) WUKOM IMVer= 2 2 - es 7 
Chemical studries7o= Salmon. 2 s=2 2.0 I 9 
reshisronies OLamarine tishes& ol ae) A a 10 
DEAS TIVAL CD SEIS LOS te ee crn fe SP AE ee WET Leis Pe Fee 1 lal 
Wibitehshes| ofthe Great bakes! 24. be 11 
HI SHeStOEMVVASCONSIN NA KeS == see se eT es a ee 13 
‘Whenpaddletishe——— 2a con Bit cri hale Big one Be Aes 14 
POISONOUS ACHIONNOlM ar TOG ks ee 14 
Hishesomiheseanamoamecionie a@ss 20 fail Paes ces ee ee allED 
LETH MO AIS) ea Ye Ns ee a ey ee ee ree eer eee Deen 16 
Miserotatish inecompating mialariae == 8 2s 16 
Cooperation in antimalaria campaign _____--______________________ 16 
Conditions governing abundance of mosquito-destroying fish ________ va 
MOSCtucOTCOnLroOlIn northernswaterss t= ss ee eee ee 18 
ISH Culiiralexperiment«W Ok. = 25. eee ke ee 19 
Experiments in propagating and rearing fish in ponds______________ 19 
Water beetles in relation to pond culture_______________-__-_-____ 20 
Studies of Salmonide in relation to fish culture______-_-_-____-_ 20 
MinnowsanErelatoneo: fisheeulittres 2 1 eee 21 
ene WAL Orns Ole DOROKOULIGhae Sct a oe eS a eM ed Pa 
Hradicationvof some objectionable plants___-_-_- =» -- 24 
SC eSsO MSN MGI SCH Seeee ace emer anes fe rie 25 
MOTEDUItYAIM PIKe-Dereh erases. = Tete ATi es Ae 25 
ADHoOrMAlsconditlons) Of ish OVaAries=—o8 5-2 st) a eee 25 
DiSea setOfereSecued sii s bee ee ees a 26 
Parasitic Latworms on fresh-water fishes. - = = ee 26 
Treatment of Ichthyophthirius disease______________.___.____ Or 
Oceanosraphic) and Jdimnolosicalistudies= 1 Pe De 
imvesnfahions le therA tant ews! 2 es Mets) ye os SN De te 28 
SUEVEViOnChCSapCakenb aya. tas a 29 
Survey of selected areas in Mississippi River______________________ 29 
HUME SHObe nian dul akeg = seers nas ae ee 30: 
Agar-agar and other gelatins from seaweed_________---____________.____ 31 
MUTCLOVSKGt meee eames Seana RY 2 Rms Meet HER er NN i aes) OE ee 32° 
InVvestieatonus ot. oyster CulbUre..3 = Set a 32 
Effect of pollutions upon propagation of oysters____-___________ 33: 
TLCS AVC DU SSe Saememeees ee Nome St en ae ee 35 
[Ela] Op Fen INO ay (OE TRADI (a ISL SS Ea A ee ee ee ee 35 
Rrolech Ono Roussel sae tt os Cis SB Pee A i ad oe ta 35, 
Musselssurveysinsupper Mississippl Riveria) 222 3 36) 
Experiments relating to mussel propagation__________.-_._____ 36: 
Investigations in“thevkentucky Rivers ee 37 
ie biglozicalsabordtories=- = = hore ee ee ee 387 
a oe ponds, VIII to the Report of the U. S. Commissioner of Fisheries for 1921. B. F. 
oc. No 
2 With the collaboration of the investigators. 
3 
