102 Proceedings Columbia Biochemical Association [Sept. 



method, in which the house current of iio volts was reduced to 70 

 volts by lamps in parallel and passed through glass-distilled water 

 by means of platinum electrodes, was used as a medium in which 

 cultures of Paramecium and other protozoa were permitted to rest. 

 Drop-ctilture slides were also made of these cultures in hanging 

 drops of the platinum black. In all cases there was no augmenta- 

 tion of division-frequence or size of the organism, nor any evi- 

 dence of toxicity. Attempts with a Solution of mastic in ether and 

 alcohol, which gave beautiful pictures under the Dunkelf eldtheleuch- 

 tung of Zeiss, were not clear in their results. The colloidal Solu- 

 tion was dialyzed for seven days in a fish-bladder, which freed it 

 from the ether and alcohol, leaving a colloidal mass with excellent 

 brownian movement. However, there is good reason to believe that 

 this is not toxic in any way on protozoa. No attempt was made to 

 " ultra-filter " the colloidal Solutions, in order to study the effects of 

 small and larger colloidal particles upon protozoa, because of the 

 apparent indifference of the organisms to the mixed Solution. 



9. Larvae of Lepidoptera obtained with sulfuric acid. Max 

 Morse, für L. B. Ripley. (Boardjnan Laboratories, Trinity Col- 

 lege, Hartford, Conn.) Larvae were obtained from unfertilized 

 eggs of the moth, Cecropia, by painting them with Baker's conc. 

 sulfuric acid (sp. g. 1.84) for from 3 to 6 seconds and immediafely 

 washing in pure water until entirely free from the acid. They were 

 then left to dry and to develop. Checks were made by treating one- 

 half of the batch from a given female with the acid and leaving 

 the other half untouched. The females had been raised and 

 isolated, from cocoons. The typical blueing of the developing eggs 

 could be observed in the early stages of the eggs treated with acid 

 while the control eggs remained white. The larvae emerged sev- 

 eral days later in the case of the artificially fertilized eggs than in 

 those normally fertilized. The percentage of errors was low. 



The larvae after emerging from the eggs were fed upon wild 

 cherry, but thus far they have not been carried to the adult stage. 

 This is now being tried. Petrunkevitch, Tichomorow and others 

 have succeeded in obtaining larvae from silk-worm eggs by artificial 

 means, but Cecropia has thus far failed to yield larvae under arti- 

 ficial conditions. Short exposure and thorough washing may be the 

 key to the success obtained in the present case. 



