;o6 



NA TURE 



[January 26, 1899 



in minute detail the histology of certain parts of the body, 

 especially the gills and mantle lobes, the alimentary canal and 

 liver. We give figures and descriptions of these structures in 

 both normal and abnormal conditions. 



12 We have also worked out the distribution and probable 

 function of a miuutc muscle, which we believe to be the 

 modified representative of the protractor pedis muscle of some 

 other molluscs. 



(31 A diseased conditi<m we found in certain American 

 oysters very soon brought us into contact with the vexed 

 question of the " greening " of oysters, and one of the first 

 results we arrived at was that there are several distiiul hinds 

 of greenness in oysters. Some of them, such as the green 

 Marennes oysters, and those of some rivers on the Essex coast 

 are healthy ; while others, such as some Falmouth oysters, con- 

 taining copper, and some American oysters re-bedded on our 

 coast, and which have the pale-green " leucocytosis " described 

 in our former paper to the Royal Society, are not in a healthy 

 state. 



(4) Some forms of greenness {e.g. the leucocytosis) are 

 certainly associated with the presence of a greatly increased 

 amount of copper in the oyster, while other forms of greenness 

 \e.g. that of the Marennes oysters) have no connection with 

 copper, but depend upon the piesence of a special pigment, 

 " mareniiin." 



We are able, in the main, to support Ray Lankester in his 

 observations on Marennes oysters ; but we regard the wandering 

 am'cboid granular cells on the surface of the gills as leucocytes 

 which have escaped from the blood spaces, and have probably 

 assumed a phagocytic function. 



(5) We see no rea.son to think that any iron which maybe 

 associated with any marennin in the gills, cVc. , is taken in 

 through the surface epithelium of the gill and palps, but regard 

 it, like the rest of the iron in the body, as a product of 

 ordinary digestion and absorption in the alimentary canal and 

 liver. 



6) We do not find that there is any excessive amount of iron 

 in the green Marennes oyster compared with the colourless 

 oyster, nor do the green parts (gills, palp, &c. ) of the Marennes 

 oyster contain either absolutely or relatively to the colourless 

 parts (mantle, i\:c. ) more iron than colourless oysters. We 

 therefore conclude that there is no connection between the 

 green colour of the " lluitres de Marennes" and the iron they 

 may contain. 



(7) On the other hand, we do find by quantitative analysis 

 that there is more copper in the green American oyster than in 

 the colourless one ; and more proportionately in the greener 

 parts than in those that are less green. We therefore conclude 

 that their green colour is due to copper. We also find a 

 greater quantity of iron in those green American oysters than in 

 the colourless : but this excess is, proportionately, considerably 

 less than that of the copper. 



(8) In the Falmouth oysters, containing an excessive amount 

 of copper, we find that much of the copper is certainly mechan- 

 ically attached to the surface of the body, and is in a form 

 insoluble in water, probably as a basic carlronate. In addition 

 to this, however, the Falmouth oyster maycontain a much larger 

 amount of copper in its tissues than does the normal colourless 

 oyster. In these Falmouth oysters the cause of the green 

 colour may be the same as in the green American oyster. 



(9) By treating sections of diseased American oysters under 

 the microscope with potassium ferrocyanide and various other 

 reagents, we find that the copper reactions correspond in 

 distribution with the green coloration ; and we find, moreover, 

 from these micro-chemical observations that the copper is 

 situated in the blood-cells or leucocytes, which are greatly 

 increased in number. This condition may be described as a 

 green leucocytosis, in which copper in notable amount is stored 

 up in the leucocytes. 



(101 We find that an aqueous solution of pure h.vmatoxylin is 

 an extremely delicate test for copper, just as Macallum found it 

 to be for iron. 



(11) Experiments in feeding oysters with weak solutions of 

 various copper and iron salts gave no definite results, certainly 

 no clear evidence of any absorption of the melals accompanied 

 by " greening." 



(12) Although we did not find the Bacillus typhosus in any 

 oysters obtained from the sea or from the markets, yet in our 

 experimental oysters inoculated with typhoid we were able to 

 recover the organism from the body of the oyster up to the 



tenth day. We show that the typhoid bacillus does not increase 

 in the body or in the tissues of the oyster, and our figures 

 indicate that the bacilli perish in the intestine. 



(13) Our experiments showed that sea-water was inimical to 

 the growth of the typhoid bacilli. Although their presence was 

 demonstrated in one case on the twenty-first day after addition 

 to the water, .still there appeared to be no initial or subsequent 

 multiplication of the bacilli. 



(14) In our experiments in washing infected oysters in a stream 

 of clean sea-water the results were definite and uniform; there 

 was a great diminution or total disappearance of the typhoid 

 bacilli in from one Uy seven days. 



(15) The colon group of bacilli is frequently found in shell- 

 fish as sold in towns, and especially in the oyster ; but we have 

 no evidence that it occurs in mollusca living in pure sea-water. 

 The natural inference that the presence of the colon bacillus 

 invariably indicates sewage contamination must, however, not 

 be considered established without further investigation. 



(16) The colon group may be separated into two divisions : 



(1) those giving the typical reactions of the colon bacillus, and 



(2) those giving corresponding negative reactions, and so ap- 

 proaching the typhoid type : but in no case was an organism 

 giving all the reactions of the B. typhosus isolated. It ought 

 to be remembered, however, that our samples of oysters, 

 although of various kinds and from different sources, were in no 

 case, so far as we are aware, derived from a bed known to be 

 contaminated or suspected of typhoid. 



(17) We have shown also the frequent occurrence, in various 

 shell-fish from the shops, of anaerobic spore-bearing bacilli 

 giving the characteristics of the B. euteritidis sporogenes 

 recently described by Klein. 



(18) As the result of our work, we make certain re 

 commendations as to the sanitary regulation and registration o 

 the oyster beds, and as to quarantine for oysters imported from 

 abroad. 



NO. I 526, VOL. 59] 



THE DUKE OF DEVONSHIRE ON 

 SECOND A R Y ED UCA TION. 

 'T'HF Duke of Devonshire opened the new building of the 

 •^ Municipal Technical College at Derby on Thursday last ; 

 and in the course of an address delivered at a luncheon given by 

 the Mayor of Derby on that occasion, lu- is reported by the 

 Times to have made the following remarks upon the value of 

 scientific instruction and the reform of secondary education. 



The inhabitants of Derby had not up to the present time 

 enjoyed all the advantages in obtaining a scientific education 

 which wtiuld have been so useful to a town possessing so many, 

 so large, and so varied industries. But science instruction in 

 Derby was now, he trusted, entering upon a new course, and he 

 had little doubt that the instruction in science which would be 

 carried on in that building would be as thorough as that which 

 had hitheito been accomplished in the art school. Though 

 they had made a great step in the erection and completion ot 

 these buildings, a great deal still remained to be done. The 

 erection of the most complete buildings and the calling of them 

 a college would not be of much use unless at the came time they 

 were able to obtain a competent staff of teachers. That, he had 

 no doubt, had already been done ; but, even when they had 

 done that, they must remember that independent classes and 

 courses of lectures, useful as they might be in enabling students 

 to acquire certain branches of knowledge which would be of use 

 to them in future years, would not, unless they were organised 

 on the principles to some extent which prevailed in our older 

 schools and colleges, provide that intellectual training and that 

 mental discipline which was more valuable than any acquired 

 knowledge. 



He and many with him, much more able than himself, had 

 during a good many years advocated the absolute national 

 necessity of giving to our people a belter technical, artistic, and 

 scientific training. lie had urged it in the interests of the 

 maintenance of our industrial supremacy and in the interests of our 

 industrial anil commercial existence. The necessity for placing 

 these means of technical instruction within the reach of our 

 people was now universally admitted. There was a movement 

 m this direction in every part of the country, and, in addition 

 to what had hitherto been known as the technical educa- 

 tion movement, there was an equally strong desire for the 

 addition of what was termed commercial education. But what 



