76 DEPARTMENT OF THE NAVAL SERYICE 



6 GEORGE V, A. 1916 



The consignees reported the stock diseased, and eventually refused to accept any 

 further consignments, though later on shipping was resumed. The merchants were 

 alarmed, as it meant a big loss and the probable ruin of a growing industry of con- 

 siderable economic importance, and requested the biological board to investigate the 

 matter. Directed by Professor A. B. Macallum, Toronto University, secretary-treas- 

 urer of the board, I went to Buctouche, inspected storage and other conditions, and 

 brought away samples of water and lots of clams from several trays for study at the 

 Marine Biological Station at St. Andrews, which were later supplemented by a special 

 lot from one of the firms. They were all transferred to wooden tanks of sea-water, 

 away from direct light, and jets were kept constantly running to renew and aerate it. 



It must be noted that the salinity of this water is greater than that of the moor- 

 ing grounds at Buctouche, where at low tide the specific gravity was only 1-01Y8 and 

 at high tide 1-0202', but at the station it registers 1-0242.5, which was maintained 

 fairly constant throughout, for the reservoirs supplying the tanks are always refilled 

 at high tide. No ill-efiects, however, were perceptible during the three or four weeks 

 the bulk of the stock were thus under observation, which implies that the quahaug 

 possesses a considerable power of resistance to osmotic pressure. 



EXAMINATION AND TESTS. 



An extended microscopic examination of the fluids and organs of many was 

 made, but no trace of disease, due to pathological causes, could be found; a finding 

 accentuated by the fact of only one death occurring among the several hundreds kept 

 in the trays. It died the day after its arrival at the station. 



It was conjectured, however, that the series of rather sudden changes of tem- 

 perature from the storage trays at 70° F. to a sealed box-ear at 45° or 50° for a week* 

 or more followed by 80° or 90° F. at the point of destination, might cause a high 

 death-rate of clams kept long in confinement and raked while they were in a reduced 

 condition. To test this, a set of eight were put in the station ice-house for three 

 days in a temperature ranging from 45° to 48°, and were then exposed to the open 

 air at a mean of 60°, the maximum (one instance) being 72°. At the end of three 

 days all were dead but one, which on dissection showed very feeble signs of life. 



Another lot of ten was taken directly from the trays and exposed for fourteen 

 days in the open air. They were all alive at the end of that time, and were returned 

 to the trays where they still live, August 25. 



These experiments seem to confirm the suspicion that sudden alterations of tem- 

 perature are fatal. It will be seen, too, that in some respects the test was not so 

 severe as the actual shipping. The ice-house is well ventilated; the duration of expo- 

 sure therein was three days, not seven; and the average and maximum temperature 

 of the weather was less than in Chicago when the last three shipments arrived. The 

 contrast, however, is great — the first lot all died, the second, exposed longer, survived 

 the test. The maintenance of a uniform average temperature during transit and 

 marketing seems all-important. 



A lot of ten were ' rapped " and exposed for six or seven days, and two died 

 after being returned to the water. Of the eight mentioned above, which were sub- 

 jected to a low temperature in the ice-house, four had been previously " rapped." 

 While the data, then, are too meagre and uncertain to warrant any general conclu- 

 sion as to the effects of this means of testing the soundness of clams, some considera- 

 tions seem to point 'to it being injurious, and hence it should, if possible, be elim- 

 inated. 



A general falliiig-off in weight resulted from all exposures. A lot of ten, wiped 

 carefully, were weighed, and at the end of six days, reweighed. The loss ranged 

 from 8 per cent to 20 per cent, or an average of 12 per cent, and the larger ones 

 invariably showed the greater reduction, the two heaviest, of 220 and 246 grammes, 

 respectively, losing 18 per cent. As no solid matter was excreted, the loss is clearly 



• After this had been written I was informed by the shipper that the temperature of the 

 iced car, ten hours after sealing, was 40°P. 4 



