1882.] 



MICROSCOPICAL JOURNAL. 



197 



seem to me any other theoretical 

 interpretation of the facts so sugges- 

 tive as this of the action of living 

 organisms tenanting its tissues. Dr. 

 Sternberg, of the National Board of 

 Health, has shown that the minute 

 organisms found in his own saliva, 

 while he was in perfect health, were, 

 by inoculation, deadly poisonous to 

 rabbits. So that we may reason by 

 analogy that a comparatively innocent 

 or even useful organism to a support- 

 ing plant may be decidedly harmful 

 when transferred to ourselves. 



Heliopelta Lewenhokii. 



In looking over a deposit of weed 

 from Long Island Sound, I found 

 some thirty or more specimens of H. 

 Lewe?ihokii^ and, not knowing that 

 they were found in recent gatherings, 

 I wrote to my correspondent, Mr. 

 Charles Stodder, and he says in re- 

 ply, that " I have never seen a record 

 of Heliopelta having been found re- 

 cent ; if you are not mistaken in the 

 genus, it is an important discovery. 

 There is no reason why it should not 

 be found living. Ehrenberg, thirty 

 years and more ago, designated many 

 forms as fossil only, but many of 

 them have since been found in re- 

 cent deposits." I should be pleased 

 to hear from diatom collectors if they 

 have seen any, and can send a slide 

 for study to any one who will write 

 to me about it. 



Thos. Christian. 



Richmond, Va. 



Tadpoles. 



About the middle of last May I se- 

 cured a number of tadpoles to make 

 observations upon the caudal circula- 

 tion — each individual had only the 

 left eye open. In three days the other 

 appeared, and in about the same time 

 after that the right leg presented it- 

 self, since when no other visible 

 changes have occurred in form, size, 

 color, or demeanor. 



That solitary undemonstrative leg 



has hung, swung, floated and waved 

 behind through four warm, dreary, 

 summer months, as useless to all in- 

 tents as a Chinaman's pigtail, and it 

 still waves — active, vigorous and con- 

 tented. What will these changeless 

 tadpoles ever come to be ? One leg 

 has evoluted, the other involuted ; 

 and of the little rotund body it may 

 with propriety be said, that " thereby 

 hangs two tails, one of which will ul- 

 timately be spelled without an egotis- 

 tical vowel. But the question is, how 

 long will the other continue to wag 

 the little tadpole ? It is certainly a 

 case of arrest of development — but 

 why ? Every condition known has 

 been continuously supplied — food, 

 water, muck, sunlight, shade, warmth, 

 etc., but they are only little tadpoles 

 still. P. L. Hatch. 



Minneapolis, Minn. 



EDITORIAL. 



Subscriptions. — Remittances for subscrip- 

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 money received by open mail. 



The JouKNAL is issued on the 15th day of each 

 month. Subscribers who do not receive their copies 

 at the usual time are requested to inform the Pub- 

 lisher of the fact. 



Committee on Ruled Plates. — 

 At the meeting of the Section of His- 

 tology and Microscopy of the A. A. A. 

 S., at Montreal, after the reading 

 of Prof. W. A. Rogers' paper on 

 ruled lines, a resolution was offered 

 that a committee be appointed 

 to receive ruled plates from dif- 

 ferent makers that might be offered 

 for examination in accordance with 

 the suggestions made by Prof. Rogers. 

 After some discussion the resolution 

 was carried, but it was afterward de- 

 cided to postpone the appointment of 

 the committee until some future time. 



We regard this as a great step to- 

 ward tiie settlement of the question 

 of the practical limit of resolution, in- 

 dependent of any theoretical consid- 



