38 



SCIENCE. 



[Vol. XXII. No 546 



of the plant and by assimilation assist in its nourishment and 

 growth. 



When the work is completed, the leaf unfolds, the tentacles 

 uncoil and again fold backward, leaving the skeleton of the 

 insect in the centre of the leaf as a warning to all passing 

 insects. A careful observation of the plants when in active 

 growing condition will show all stages of the process. Some 

 leaves will be folded up enclosing fresh insects, while many more 

 will be seen spread open with the skeletons on their upper surface. 

 Having finished their meal they are ready for the next customer. 

 Occasionally the living insect will be found struggling to free 

 itself from the adhesive secretion of the glands and the grasping 

 tentacles that threaten its life. The larger insects often manage 

 to free themselves and escape the fate that overtakes the less 

 fortunate. I have seen the common house fly after being held for 

 sometime finally extricate itself and fly away. 



A great variety of insects, such as mosquitoes, small flies and 

 bugs, become the victims of this carnivorous plant. Small spiders 

 with their soft bodies seem to be especially adapted to supplying 

 its demands. 



The plant, which has but a few very small roots, can be easily 

 transplanted to boxes where it can be more readily observed. A 

 sufficient amount of the adhering soil should be taken up with it, 

 which can be readily done by means of a common garden trowel. 



In some experiments lately made I find that it generally takes 

 from 24 to 48 hours for the leaf to become completely folded over 

 an insect. Small house flies required in some instances 48 hours, 

 and it was nearly two weeks before the leaf again unfolded. 

 Small spiders, having softer bodies, were digested in less time. 

 Small pieces of cooked beefsteak placed on the leaves at noon were 

 enfolded by the next morning. At first the leaves appeared to 

 be stimulated to extra activity, but the beef did not seem to be 

 adapted to the sustenance of the plant. After a few days the 

 leaves, instead of unfolding gradually wasted away, the tentacles 

 withered and finally the whole leaf died, leaving the beef ap- 

 parently but little changed. Pieces of wood or solid vegetable 

 fibre placed on the leaves would be partly enfolded but only 

 remain so for a day or tw<j. Tender vegetable tissues in 48 hours 

 were reduced to an appai'ently decomijosed pulp. 



Besides Drosera capillaris we have here in Volusia County two 

 other species of Drosera; D. brevifolia, a smaller plant, not very 

 common, grows in higher and dryer situations. The leaves are 

 only about one-half inch in length, while the pretty flowers are 

 quite conspicuous, being one half inch in diameter. 



D. longifolia is occasionally seen on swampy and overflowed 

 lands, where it is found floating during high water, the few roots 

 taking a feeble hold of the soil as the water recedes. 



The Venus's fly-trap (Dioncea muscipvla), also belonging to the 

 order Droseracaa, I think has not been found so far south as 

 Florida. 



The spotted Trumpet Leaf {Sarracenia variolaris), also an 

 insectivorous plant, is common here. 



Bejaria racemosa, a shrub growing 2 or 5 feet high, with large 

 and showy white flowers, secretes a viscid, sticky substance on 

 the stems below the flowers, thus entrapping many insects. It is 

 often called Fly Catcher. 



It is the general law in vegetable physiology that plant life 

 receives nourishment from two sources — First from the more 

 solid organic and mineral substances supplying phosphorus, 

 potassium, sulphur, ammonia, etc., taken up by the rootlets and 

 carried in solution to every part of the plant to he utilized in the 

 proce.'^s of growth, and, Sfcond, from the gaseous substances, 

 oxygen, carbon dioxide, nitrogen and ammonia, drawn from the 

 atmosphere through the stomata of the leaves. In carnivorous 

 plants alone do we find the power of dissolving and appropriating 

 organic substances through the leaves. In this power there is an 

 approach made toward the function of the stomach in animals, 

 thus forming another connecting link between the vegetable 

 kingdom and those forms of life so nearly on the dividing line 

 between the animal and the vegetable that it is sometimes diffi- 

 cult to determine on which side tbey really belong, and demon- 

 strating to the student of biology that there is a unity m all 

 life. 



QUANTITY AND QUALITY OF MILK. 



BY W. W. COOKE, STATE AGKICULTURAL EXPERIMENT STATION, BUR- 

 LINGTON, VT. 



Several attempts have been made to measure the effect of th& 

 period of lactation of the cow on the quantity and quality of 

 the milk. In nearly, if not all, of these cases no account is takeit' 

 of the food or the <;oEditions. In this note it is intended to show 

 how these changes during the period of lactation are modified by 

 the abundance or scarcity of the food of the cow. 



Most of the cows of Vermont calve in the spring, from February 

 to May. We have the records of twenty such herds of about 

 twenty cows each. Averaging these records, we get figures based 

 on the doings of over four hundred cows. Hence the results ought 

 to be quite reliable. 



All results are calculated to thirty days in a month. 



Average dally yield of milk 

 per herd, pounds 



Ratio of different months. If 

 June l3 100 



Average per cent of fat In 

 milk 



Ratio of different months, if 

 June Is 100 



Average dally yield of but- 

 ter fat per herd, pounds 



Ratio of different months, If 

 June is 100 



These cows were fed but little grain at the barn. They were- 

 turned to pasture in May and fed no grain while on pasture. A& 

 the pastures dried up in August and September, but little care was 

 taken to keep up the flow of milk. Almost no grain was fed, and 

 not much of fodder-corn or of fall mowings. When they came 

 to the barn in November, no pains were taken, in most cases, to 

 keep them along in milk. The feeding, then, may be said to be 

 rather poor at the two ends of the season and an abundance of the 

 best of feed in the middle. 



Under these conditions there is a marked increase in the quan- 

 tity of milk under better feed, reaching its height when the feed 

 is best in June and skrinking still more markedly when cold 

 weather and short feed occur in Nevember. The changes in 

 quality are especially worthy of note. There is a prevailing idea 

 that when covv's go out to grass the milk gets poorer in quality as 

 it increases in volume. Some States recognize this belief in their 

 statutes by lowering the legal milk standard during May and June. 

 Many tests at this station during four consecutive seasons have 

 shown the incorrectness of this belief, and the figures of these 400 

 cows show the same very conclusively. 



The per cent of fat is lowest just after they calve, and there is 

 a rapid increase when they go to pasture, and a continued increase 

 each month until at the last the increase is very rapid. 



It is to be noted, however, that this increase of fat per cent is 

 not enough to counterbalance the decrease in the weight of the 

 milk, so that the total daily fat decreases during the fall months 

 in spite of the increased rickness of the milk. 



If these records are compared with those of the station herd 

 that have been full fed all the year, it will be seen that there are 

 no such violent changes. When the cows go to pasture the milk 

 increases quite a little, but the fat remains about the same, and 

 for the first eight months of lactation there is only a slight change 

 in per cent fat, and no very large decrease, and no sudden decrease 

 in quantity of milk. Also, it will be noted that in our herd there 

 is not so large an increase in per cent fat at the end of the period 



