PEOGEESS OF MICEOSCOPICAL SCIENCE. 153 



shown that one or two instances of cholera were connected with the 

 presence of certain organisms in the air ; but on going into the matter 

 he has been assured that this has not been the case. 



Dr. Cunningham has been at considerable pains in carrying out 

 bis experiments, and indeed on this subject we must say that he has 

 taken every precaution to avoid failure. Esjjecially would we refer to 

 the excellent modification of Dr. Maddox's apparatus which he has 

 employed in his experiments, for this is an instrument which may be 

 used with excellent results in some future inquiries. We must also 

 award very high praise to the author for the care and discretion which 

 he has shown in conducting his experiments, and for the accuracy with 

 which he has stated the results. Beyond this, however, we have little 

 to say in his praise ; for it seems to us that he has gone over ground 

 that ought to have been pregnant with valuable results if the experi- 

 menter had employed the proper means of research, and those we 

 think Dr. Cunningham failed to apply. Why, for instance, should he 

 have used such low powers in his observations ? Surely he did not 

 expect to find many organisms with objectives magnifying 400 dia- 

 meters ; the microscopist of the present day would not be so well 

 employed with such a magnifying power as Leiiwenhoek was with his 

 lens. And so far as we can see, the author, save in one or two instances, 

 used no higher object-glass. How he could expect to see everything 

 that was present with such amjilification is to us perfectly unintel- 

 ligible. If Mr. Dallinger had had Dr. Cunningham's opportunities, we 

 doubt not he would have found many organisms, as we may judge by 

 his published j^apers. So far as he has gone. Dr. Cunningham has 

 nothing to tell. But may we not say to him, look again ? With a 

 fV ^^ Toi ^^^ proper arrangements for light, we may expect much 

 better results than those he has laid before us in his present by no 

 means uninteresting volume. J. D. 



PEOGEESS OF MICEOSCOPICAL SCIENCE. 



Dr. Carpenter's Views on the Subject of Eozoon. — In our last 

 number but one we gave ample space toward an explanation of 

 Mr. Carter's opinions on the subject of Eozoon ; and it will be 

 remembered that he takes the same view of this structure as that 

 held by Messrs. King and Kowney. We have now the opportunity of 

 laying Dr. Carpenter's views forward, accompanied by an excellent 

 woodcut of one of the calcareous lamella) of Eozoon, which the editor 

 of ' Nature ' has kindly placed at our disposal. In Dr. Carpenter's 

 recent paper in the ' Annals of Natural History' for June (1874), 

 the subject is very fully gone into, and to that we must refer those 

 of our readers who are interested in this question. However, with the 

 aid of the woodcut we may extract some of the author's remarks 

 which bear on the point of controversy. Dr. Carpenter says — 



" My true ' nummuline wall ' is the representative of that which, 



M 2 



