Plasma transfusions are often used clinically to correct hypoproteinemia resulting from malnutrition although the results are often disappointing in the severe cases. It seemed advisable, therefore, to study experimentally the effect of intravenous plasma in dogs depleted by a non-protein diet which has been shown by Weech (1) and ourselves (2) to produce a rapid fall in the albumin fraction of the blood. Holman, Mahoney, and Whipple (3) were the first to study the metabolic effect of plasma transfusions in the dog and they showed that protein given in this way led to positive nitrogen balance but only when dog plasma was used. These findings were confirmed by later studies (4, 5). More recently Kremen et al. have reported similar findings with human plasma in human beings but not with bovine plasma (6). In protein-depleted dogs Shearburn (7) found that one plasma transfusion calculated to restore the plasma protein deficiency had only a transient influence on plasma volume and no effect on the hypoproteinemia, whereas smaller amounts given once or twice a day for 2 weeks led to a gradual return of the plasma protein to normal. ProceduresThe dietary method used to produce hypoalbuminemia was similar to that devised by Weech (1) except that a solution was used and administered by garage twice daily (2). The energy value was 50 calories per kilo per day and the nitrogen intake due largely to vitamin B complex was under 20 rag. per kilo per day. A period of 3 weeks was used for depletion; the 4th week was used for therapy and the depletion then continued for 2 more weeks. Thus each experiment lasted 6 weeks. Under such a non-protein r6gime hypoalbuminemia rapidly develops except that occasionally it is masked by hemoconcentration which is revealed by a rise in the hematocrit reading (8). However, in the present experiments plasma volumes were measured to circumvent this state of affairs; the method used was described in a previous paper in this series (9).The amount of plasma given during the 4th week was determined by measuring its nitrogen content. A dose of 0.5 gm. of nitrogen per kilo per day was given, which was the same we used in other regeneration experiments in which hydrolyzed protein was used (2). In terms of protein this represented a little over 3 gin. per kilo per day, which is somewhat greater than 2.5 gin. employed by Weech. It was 1 on

SUMMARYThe effects of light, temperature and infestation by Aphis fabae Scop, on Vicia faba L. were examined in a factorial experiment. Light was 1116 or 40 //mol m"^ s~^ PPFD and temperature 15/10 °C or 25/20 °C (16 h day/8 h night). Plants and aphids were harvested after 9 d at 25/ 20 °C and 13 dat 15/10 °C. High hght and high temperature increased the relative growth rate (RGR) of aphid colonies, but without interaction. Under high light, alatae produced more nymphs which grew larger. High temperature did not affect nymph production, but mature apterae weighed less. More honeydew was produced at high light. High temperature increased honeydew at high light, but decreased it at low. Reduction in dry weight (d.w.) of infested plants was similar to the calculated dry matter (d.m.) ingested by the aphids except at high light/low temperature, where it was much less. Calculated NAR was increased by high light, but reduced by high temperature. In infested plants, 'true' NAR (calculated from plant d.w. + ingested d.m.) was compared with 'apparent' NAR (calculated from plant d.w. alone). Infestation decreased 'apparent' NAR, but the effect was small at high light/low temperature because 'true' NAR increased. Infested plants at low light/high temperature had negative 'apparent' NARs. High light and high temperature generally decreased leaf diffusive resistance, except that uninfested plants at high light/low temperature had large values. Stem, leaf and root d.w. were all increased by high light and decreased by infestation. Leaf carbohydrate showed similar responses. Chlorophylls were reduced at high light, particularly at low temperature in uninfested plants. These plants showed positive relationships between chlorophyll and (1) the starch: sucrose ratio and (2) leaf total nitrogen, but a negative relationship with leaf diffusive resistance. Leaf potassium (K) and amino nitrogen showed only small responses to light and temperature. Aphids retained > 80 % of N ingested and < 20 % of K. Ingested material contained more K than N, but the ratio of both to carbohydrate was much greater under low light, particularly at high temperature. Aphids under these conditions appeared starved of carbohydrate. Low light increased the proportions of proline, amides and ammonia in both leaf extracts and aphid honeydew.

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