October 11, 1895.] 



SCIENCE. 



461 



to any diseased conditions; how long it re- 

 mains in the' alimentary canal; whether it 

 remains and grows in the pallial cavitj^, on 

 the surface of the mantle and branchial 

 folds; and whether it produces any altered 

 condition of these parts that can be recog- 

 nized by the eye on opening the oyster. 



7. To determine whether an o jester can 

 free its alimentary canal and pallial cavity 

 from the typhoid organism when placed in 

 a stream of clean sea water; and, if so, how 

 long would be required, under average con- 

 ditions, to render infected oysters practically 

 harmless. 



B. The methods which we employed in 

 attaining these objects were as follows: — 



1. Observations upon oysters laid down 

 in the sea, at Poi"t Erin — 



(a) Sunk in 5 fathoms in the bay, in 

 pure water. 



(6) Deposited in shore pool, but in clean 

 water. 



(c) Laid down in three different spots in 

 more or less close proximity to the main 

 drain pipe, opening into the sea below low- 

 water mark. 



These were to ascertain differences of fat- 

 tening, condition, mortality, and the ac- 

 quisition of deleterious properties as the 

 result of sewage contamination. 



2. Observations upon oysters subjected to 

 various abnormal conditions in the labora- 

 tory.* 



(a) A series of oysters placed in sea 

 water and allowed to stagnate, in order to 

 iietermine effect of non-aeration. 



(6) Similar series in water kept period- 

 ically aerated. 



(c) A series placed in sea water to which 

 a given quantity of fresh (tap) water was 

 added daily, to determine effect of reduc- 

 tion of salinity. 



* The oysters were kept in basins in cool rooms of 

 constant temperature, shaded from the sun, both at 

 the Port Erin Biological Station and also in the 

 Pathological and Zoological Laboratories at Univer- 

 sity College, Liverpool. 



(d) A series of oysters weighed approxi- 

 mately, and fed upon the following sub- 

 stances, viz.: — 



(1) Oatmeal. 



(2) Flour. 



(3) Sugar. 



(4) Broth. 



(5) Living Protophyta (Diatoms, Des- 

 mids, Alg£e). 



(6) Living Protozoa (Infusoria, etc.). 



(7) Earth. 



In this series of experiments the oysters 

 were fed everj^ morning and the water 

 aerated, but not changed (evaporation was 

 compensated for by the addition of a little 

 tap water as required). The oysters were 

 weighed from time to time, and observa- 

 tions made upon the apparently harmful or 

 beneficial effects of the above methods of 

 treatment. 



(e) A series of oysters placed in sea water 

 to which was added daily^ 



(1) Healthy faecal matter. 



(2) Typhoid faecal matter. 



(3) Pure cultivations of the typhoid 

 bacillus. 



The oysters were carefully examined to 

 determine their condition, with special refer- 

 ence to condition of branchia, alimentary 

 canal, adductor muscle, and viscera gener- 

 ally. The contents of the rectum, as well as 

 the water in the pallial cavity , were subj ected 

 to bacteriological analysis to determine the 

 number of micro-organisms present, as well 

 as the identity of the typhoid or other 

 pathogenic organisms. 



C. The following is a summary of the 

 results obtained so far: — 



We consider that these results are based 

 upon tentative experiments, and serve only 

 to indicate further any definite lines of re- 

 search. They must not be regarded as con- 

 clusive. We feel strongly that all the ex- 

 periments must be repeated and extended 

 in several directions. 



Our experiments demonstrate: — 



